Integrated mid-infrared, far infrared and terahertz optical Hall effect (OHE) instrument, and method of use

A method of determining at least some of the free charge carrier concentration and/or mobility in a sample, said sample having a back side and a surface and being transparent or semi-transparent or substantially opaque beyond some distance thereinto from a surface thereof thereinto at wavelength(s) utilized, said method comprising the steps of:

• a) providing an ellipsometer comprising:
• a source of a beam of electromagnetic radiation characterized by at least one wavelength in a selection from the group consisting of the:
• Visual;
• MIR;
• FIR;
• and
• THz ranges;
• a polarizer;
• a stage for supporting a sample, said stage comprising an adjustable surface that is capable of orienting a surface of a sample placed thereupon via adjustment of at least one selection from the group consisting of:
• stage tip, stage tilt and rotation thereof about an axis projecting substantially normal to said stage surface, to desired value(s);
• an analyzer;
• and
• a detector of relevant electromagnetic radiation wavelengths;
• further providing a source of a magnetic field;
• b) placing a sample on said stage and adjusting said stage so that stage tip and/or stage tilt and/or rotation thereof about an axis projecting substantially normal to said stage surface are set to desired values, and so that the source of a magnetic field provides a magnetic field other than parallel thereto at said surface of said sample;
• c) while applying the source of a magnetic field to apply a selected magnitude magnetic field other than parallel thereto at the surface of said sample, causing said source of electromagnetic radiation to provide a beam of electromagnetic radiation comprising at least one wavelength of a substantially exact multiple of a an optical path length in said sample, and which beam is caused to pass through said polarizer and assume a polarization state, interact with said sample, pass through said analyzer and enter said detector, which detector produces sample characterizing data;
• d) from data accumulated by said detector with the system adjusted as described in steps b) and c), evaluating anisotropic values for at least a partial Jones or Mueller Matrix;
• and
• e) from said anisotropic values for said at least a partial Jones or Mueller Matrix determining at least one of the free charge carrier concentration and/or mobility by direct calculation rather than by a mathematical regression procedure
• said method being characterized by at least one selection from the group consisting of:
• a1′) data is accumulated with the source provided beam of electromagnetic radiation set so that it provides at least one substantially exact multiple of an optical path length within said sample;
• a2′ nine Mueller Matrix are evaluated, said nine elements being M11, M12, M13, M21, M22, M23, M31, M32 and M33, and wherein each Mueller Matrix elements M12, M13, M21, M22, M23, M31, M32 and M33 is divided by the value of M11 prior to use in evaluating free charge carrier longitudinal and transversal effective masses, concentration, mobility and type;
• a3) at least a partial Mueller matrix is determined and, of the Mueller Matrix elements M11, M12, M13, M21, M22, M23, M31, M32 and M33 that can be determined, at least M11, and at least one of M23 and M32 are, said approach to determining values for M11, and at least one of M23 and M32 being distinguished in that data is determined by a selection from the group consisting of:
• placing said sample on said stage for supporting a sample with the back side thereof in contact with said stage and obtaining a first set of data, then flipping said sample so that it's surface is in contact with said stage and obtaining a second set of data;
• and
• first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and then placing the south pole of the same or another magnet so that the south pole thereof is near the sample and obtaining a second set of data,
• followed by subtracting said second set of data from said first, or vice-versa, for each of the resulting M11, and at least one of said resulting M23 and M32 Mueller Matrix elements determined, and wherein each determined M23 and M32 is divided by M11, prior to using said resulting at least one of M23 and M32 values as data upon which to regress a model of said sample that includes free charge carrier longitudinal and transversal effective masses, concentration, mobility and type, thereby allowing their evaluation;
• a4′) at least one of M13 and M3 is determined in addition to M11 by the procedure of obtaining a first set of data with the sample back side in contact with said stage and then flipping said sample or over so that it's surface is in contact with said stage and obtaining a second set of data;
• or by first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and then placing the south pole of the same or another magnet so that the it is near the sample and obtaining a second set of data;
• and then subtracting said second set of data from said first, or vice-versa, for each of the resulting M11, and at least one of said resulting M13 and M31 Mueller Matrix elements determined, prior to using said resulting at least one of M23 and M32 and at least one of M13 and M31 values as data upon which to simultaneously regress a model of said sample that includes free charge carrier longitudinal and transversal effective masses, concentration, mobility and type, thereby allowing their evaluation
• a5′) at least a partial Mueller matrix is determined and, of the Mueller Matrix elements M11, M12, M13, M21, M22, M23, M31, M32 and M33 that can be determined, at least M11, and at least one of M13 and M31 are, said approach to determining values for M11, and at least one of M13 and M31 being distinguished in that data is determined by a selection from the group consisting of:
• placing said sample on said stage for supporting a sample with the back side thereof in contact with said stage and obtaining a first set of data, then flipping said sample so that it's surface is in contact with said stage and obtaining a second set of data;
• and
• by first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and then placing the south pole of the same or another permanent magnet so that is near the sample and obtaining a second set of data;
• and then subtracting said second set of data from said first, or vice-versa, for each of the resulting M11, and at least one of said resulting M23 and M32 Mueller Matrix elements determined, and wherein each determined M13 and M31 is divided by M11, prior to using said resulting at least one of M13 and M31 values as data upon which to regress a model of said sample that includes free charge carrier longitudinal and transversal effective masses, concentration, mobility and type, thereby allowing their evaluation;
• a6′) at least one of M32 and M23 is determined in addition to M11 by the procedure of data being determined by obtaining a first set of data with the sample back side in contact with said stage and then flipping said sample over so that it's surface is in contact with said stage and obtaining a second set of data;
• or by first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and then placing the south pole of the same or another permanent magnet so that is near the sample and obtaining a second set of data, and then subtracting said second set of data from said first for each of the resulting M11, and at least one of said resulting M23 and M32 Mueller Matrix elements determined, prior to using said resulting at least one of the M23 and M32 and at least one of M23 and M32 values as data upon which to simultaneously regress a model of said sample that includes free charge carrier longitudinal and transversal effective masses, concentration, mobility and type, thereby allowing their evaluation;
• and
• a7′) which Mueller Matrix element M11, and at least one selection from the group of elements consisting of M12, M13, M23, or at least one selection from the group of elements consisting of M12, M13, M33 is evaluated by, for each selection, a selection from the group consisting of:
• first placing said sample on said stage for supporting a sample with the back side thereof in contact with said stage and obtaining a first set of data, and second flipping said sample so that it's surface is in contact with said stage and obtaining a second set of data;
• and
• by first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and second placing the south pole of the same or another magnet so that it is near the sample and obtaining a second set of data;
• followed by subtracting the first from the second or the second from the first obtained set of data for each selection from the group of elements consisting of at least one selection from the group consisting of M12, M13, M23, or at least one selection from the group of elements consisting of M12, M13, M33;
• followed by dividing said result(s) by M11, before, from said anisotropic value(s), determining at least one of the free charge carrier concentration and/or mobility.

A stage for supporting a sample having a back side and a surface, comprising:

• a) an interface plate comprising a sample supporting stage;
• b) a magnetic casing plate for positioning at least one magnet with respect to said sample supporting stage, through an opening in said magnetic casing plate said interface plate projects;
• c) a mechanism for adjusting the tip and/or tilt of said stage with respect to a surface associated with said at least one magnet, such that said surface associated with said at least one magnet is substantially parallel to the back side of a sample placed on said sample supporting stage;
• such that in use said magnetic casing plate and interface plate are offset from one another and adjusted by said mechanism for adjusting the tip and/or tilt of said stage to provide a gap therebetween that establishes a cavity in which at least some electromagnetic radiation caused to be incident on the sample surface transmits through said sample and reflects from said surface associated with said magnet back into said sample, and
• d) a mechanism for fixing the described relationship between said magnetic casing plate and interface plate, and then allowing the tip/tilt mechanism capability be used to adjust an ellipsometer electromagnetic beam angle and/or plane of incidence thereto.

A method of determining at least one of free charge carrier concentration and/or mobility in a sample, said sample having a back side and a surface and being transparent or semi-transparent at wavelength(s) utilized, said method comprising the steps of:

• a) providing an ellipsometer comprising:
• a source of a beam of electromagnetic radiation characterized by at least one wavelength selected from the group consisting of:
• Visual;
• MIR;
• FIR;
• and
• THz ranges;
• a polarizer;
• a stage for supporting a sample;
• an analyzer;
• and
• a detector;
• b) placing a sample on said stage and adjusting said stage so that stage tip and/or stage tilt and/or rotation thereof about an axis projecting substantially normal to said stage surface are set to desired values, and so that the source of a magnetic field provides a magnetic field other than parallel thereto at said surface of said sample, and/or adjusting positioning of the source of a magnetic field which is oriented to provide a magnetic field other than parallel thereto at said surface of said sample, to achieve a desired value of magnetic field at said sample surface;
• c) while applying the source of a magnetic field to provide a selected magnitude magnetic field other than parallel thereto at the surface of said sample, causing said source of electromagnetic radiation to provide a beam of electromagnetic radiation which is caused to pass through said polarizer and assume a polarization state, interact with said sample, pass through said analyzer and enter said detector, which detector produces sample characterizing data;
• d) from data accumulated by said detector with the system adjusted as described in steps b) and c), evaluating anisotropic values for at least a partial Jones or Mueller Matrix;
• and
• e) from said values for said at least a partial Jones or Mueller Matrix determining at least one of the free charge carrier concentration and/or mobility;
• said method being characterized by at least one selection from the group consisting of:
• a1′) data is accumulated with the source provided beam of electromagnetic radiation set so that it provides at least one substantially exact multiple of an optical path length within said sample;
• a2′ nine Mueller Matrix are evaluated, said nine elements being M11, M12, M13, M21, M22, M23, M31, M32 and M33, and wherein each Mueller Matrix elements M12, M13, M21, M22, M23, M31, M32 and M33 is divided by the value of M11 prior to use in evaluating free charge carrier longitudinal and transversal effective masses, concentration, mobility and type;
• a3) at least a partial Mueller matrix is determined and, of the Mueller Matrix elements M11, M12, M13, M21, M22, M23, M31, M32 and M33 that can be determined, at least M11, and at least one of M23 and M32 are, said approach to determining values for M11, and at least one of M23 and M32 being distinguished in that data is determined by a selection from the group consisting of:
• placing said sample on said stage for supporting a sample with the back side thereof in contact with said stage and obtaining a first set of data, then flipping said sample so that it's surface is in contact with said stage and obtaining a second set of data;
• and
• first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and then placing the south pole of the same or another magnet so that the south pole thereof is near the sample and obtaining a second set of data,
• followed by subtracting said second set of data from said first, or vice-versa, for each of the resulting M11, and at least one of said resulting M23 and M32 Mueller Matrix elements determined, and wherein each determined M23 and M32 is divided by M11, prior to using said resulting at least one of M23 and M32 values as data upon which to regress a model of said sample that includes free charge carrier longitudinal and transversal effective masses, concentration, mobility and type, thereby allowing their evaluation;
• a4′) at least one of M13 and M3 is determined in addition to M11 by the procedure of obtaining a first set of data with the sample back side in contact with said stage and then flipping said sample or over so that it's surface is in contact with said stage and obtaining a second set of data;
• or by first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and then placing the south pole of the same or another magnet so that the it is near the sample and obtaining a second set of data;
• and then subtracting said second set of data from said first, or vice-versa, for each of the resulting M11, and at least one of said resulting M13 and M31 Mueller Matrix elements determined, prior to using said resulting at least one of M23 and M32 and at least one of M13 and M31 values as data upon which to simultaneously regress a model of said sample that includes free charge carrier longitudinal and transversal effective masses, concentration, mobility and type, thereby allowing their evaluation
• a5′) at least a partial Mueller matrix is determined and, of the Mueller Matrix elements M11, M12, M13, M21, M22, M23, M31, M32 and M33 that can be determined, at least M11, and at least one of M13 and M31 are, said approach to determining values for M11, and at least one of M13 and M31 being distinguished in that data is determined by a selection from the group consisting of:
• placing said sample on said stage for supporting a sample with the back side thereof in contact with said stage and obtaining a first set of data, then flipping said sample so that it's surface is in contact with said stage and obtaining a second set of data;
• and
• by first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and then placing the south pole of the same or another permanent magnet so that is near the sample and obtaining a second set of data;
• and then subtracting said second set of data from said first, or vice-versa, for each of the resulting M11, and at least one of said resulting M23 and M32 Mueller Matrix elements determined, and wherein each determined M13 and M31 is divided by M11, prior to using said resulting at least one of M13 and M31 values as data upon which to regress a model of said sample that includes free charge carrier longitudinal and transversal effective masses, concentration, mobility and type, thereby allowing their evaluation;
• a6′) at least one of M32 and M23 is determined in addition to M11 by the procedure of data being determined by obtaining a first set of data with the sample back side in contact with said stage and then flipping said sample over so that it's surface is in contact with said stage and obtaining a second set of data;
• or by first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and then placing the south pole of the same or another permanent magnet so that is near the sample and obtaining a second set of data, and then subtracting said second set of data from said first for each of the resulting M21, and at least one of said resulting M23 and M32 Mueller Matrix elements determined, prior to using said resulting at least one of the M23 and M32 and at least one of M23 and M32 values as data upon which to simultaneously regress a model of said sample that includes free charge carrier longitudinal and transversal effective masses, concentration, mobility and type, thereby allowing their evaluation;
• and
• a7′) which Mueller Matrix element M11, and at least one selection from the group of elements consisting of M12, M13, M23, or at least one selection from the group of elements consisting of M12, M13, M33 is evaluated by, for each selection, a selection from the group consisting of:
• first placing said sample on said stage for supporting a sample with the back side thereof in contact with said stage and obtaining a first set of data, and second flipping said sample so that it's surface is in contact with said stage and obtaining a second set of data;
• and
• by first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and second placing the south pole of the same or another magnet so that it is near the sample and obtaining a second set of data;
• followed by subtracting the first from the second or the second from the first obtained set of data for each selection from the group of elements consisting of at least one selection from the group consisting of M12, M13, M23, or at least one selection from the group of elements consisting of M12, M13, M33;
• followed by dividing said result(s) by M11, before, from said anisotropic value(s), determining at least one of the free charge carrier concentration and/or mobility.

A method of enhancing the capability of determining at least one of free charge carrier concentration and/or mobility in a sample having a back side and a surface, said sample being transparent or semi-transparent at wavelength(s) utilized, said method comprising the steps of:

• a) providing an ellipsometer comprising:
• a source of a beam of electromagnetic radiation characterized by at least one wavelength in a selection from the group consisting of the:
• Visual;
• MIR;
• FIR;
• and
• THz;
• ranges;
• a polarizer;
• a stage for supporting a sample;
• an analyzer;
• and
• a detector;
• and a source of a magnetic field having a surface associated therewith and which is oriented to provide a magnetic field other than parallel thereto at said surface of said sample;
• b) placing a sample on said stage and adjusting said stage so that stage tip and/or stage tilt and/or rotation thereof about an axis projecting substantially normal to said stage surface are set to desired values, and so that the source of a magnetic field provides a magnetic field other than parallel thereto at said surface of said sample, and/or further adjusting the source of a magnetic field so that it is oriented to provide a magnetic field other than parallel thereto at said surface of said sample of a desired value;
• c) while applying the source of a magnetic field to apply a magnetic field other than parallel thereto at the surface of said sample or a desired value, causing said source of electromagnetic radiation to provide a beam of electromagnetic radiation comprising at least one wavelength which is substantially a multiple of an optical path length in said sample, which beam is caused to pass through said polarizer and assume a polarization state, interact with said sample, pass through said analyzer and enter said detector, which detector produces sample characterizing data;
• d) from data accumulated by said detector with the system adjusted as described in steps b) and c), evaluating anisotropic values for at least a partial Jones or Mueller Matrix;
• and
• e) from said values for said at least a partial Jones or Mueller Matrix directly determining at least one of the free charge carrier concentration and/or mobility;
• said method being distinguished in that, while data is being accumulated by said detector, a gap is caused to exist between at least one selection from the group consisting of:
• 1) said sample backside and the sample supporting stage;
• and
• 2) said sample supporting stage and said surface associated with said source of a magnetic field which is oriented to provide a magnetic field other than parallel thereto at said surface of said sample of a desired value;
• such that a cavity is formed in which at least some electromagnetic radiation in the beam thereof directed at said sample by said source of a beam of electromagnetic radiation passes through said sample, and is coherently reflected back thereinto by said surface associated with said source of a magnetic field, thereby enhancing the signal entering the detector;
• said method being characterized by at least one selection from the group consisting of:
• a1′) data is accumulated with the source provided beam of electromagnetic radiation set so that it provides at least one substantially exact multiple of an optical path length within said sample;
• a2′ nine Mueller Matrix are evaluated, said nine elements being M11, M12, M13, M21, M22, M23, M31, M32 and M33, and wherein each Mueller Matrix elements M12, M13, M21, M22, M23, M31, M32 and M33 is divided by the value of M11 prior to use in evaluating free charge carrier longitudinal and transversal effective masses, concentration, mobility and type;
• a3) at least a partial Mueller matrix is determined and, of the Mueller Matrix elements M11, M12, M13, M21, M22, M23, M31, M32 and M33 that can be determined, at least M11, and at least one of M23 and M32 are, said approach to determining values for M11, and at least one of M23 and M32 being distinguished in that data is determined by a selection from the group consisting of:
• placing said sample on said stage for supporting a sample with the back side thereof in contact with said stage and obtaining a first set of data, then flipping said sample so that it's surface is in contact with said stage and obtaining a second set of data;
• and
• first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and then placing the south pole of the same or another magnet so that the south pole thereof is near the sample and obtaining a second set of data,
• followed by subtracting said second set of data from said first, or vice-versa, for each of the resulting M11, and at least one of said resulting M23 and M32 Mueller Matrix elements determined, and wherein each determined M23 and M32 is divided by M11, prior to using said resulting at least one of M23 and M32 values as data upon which to regress a model of said sample that includes free charge carrier longitudinal and transversal effective masses, concentration, mobility and type, thereby allowing their evaluation;
• a4′) at least one of M13 and M3 is determined in addition to M11 by the procedure of obtaining a first set of data with the sample back side in contact with said stage and then flipping said sample or over so that it's surface is in contact with said stage and obtaining a second set of data;
• or by first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and then placing the south pole of the same or another magnet so that the it is near the sample and obtaining a second set of data;
• and then subtracting said second set of data from said first, or vice-versa, for each of the resulting M11, and at least one of said resulting M13 and M31 Mueller Matrix elements determined, prior to using said resulting at least one of M23 and M32 and at least one of M13 and M31 values as data upon which to simultaneously regress a model of said sample that includes free charge carrier longitudinal and transversal effective masses, concentration, mobility and type, thereby allowing their evaluation
• a5′) at least a partial Mueller matrix is determined and, of the Mueller Matrix elements M11, M12, M13, M21, M22, M23, M31, M32 and M33 that can be determined, at least M11, and at least one of M13 and M31 are, said approach to determining values for M11, and at least one of M13 and M31 being distinguished in that data is determined by a selection from the group consisting of:
• placing said sample on said stage for supporting a sample with the back side thereof in contact with said stage and obtaining a first set of data, then flipping said sample so that it's surface is in contact with said stage and obtaining a second set of data;
• and
• by first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and then placing the south pole of the same or another permanent magnet so that is near the sample and obtaining a second set of data;
• and then subtracting said second set of data from said first, or vice-versa, for each of the resulting M11, and at least one of said resulting M23 and M32 Mueller Matrix elements determined, and wherein each determined M13 and M31 is divided by M11, prior to using said resulting at least one of M13 and M31 values as data upon which to regress a model of said sample that includes free charge carrier longitudinal and transversal effective masses, concentration, mobility and type, thereby allowing their evaluation;
• a6′) at least one of M32 and M23 is determined in addition to M11 by the procedure of data being determined by obtaining a first set of data with the sample back side in contact with said stage and then flipping said sample over so that it's surface is in contact with said stage and obtaining a second set of data;
• or by first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and then placing the south pole of the same or another permanent magnet so that is near the sample and obtaining a second set of data, and then subtracting said second set of data from said first for each of the resulting M11, and at least one of said resulting M23 and M32 Mueller Matrix elements determined, prior to using said resulting at least one of the M23 and M32 and at least one of M23 and M32 values as data upon which to simultaneously regress a model of said sample that includes free charge carrier longitudinal and transversal effective masses, concentration, mobility and type, thereby allowing their evaluation;
• and
• a7′) which Mueller Matrix element M11, and at least one selection from the group of elements consisting of M12, M13, M23, or at least one selection from the group of elements consisting of M12, M13, M33 is evaluated by, for each selection, a selection from the group consisting of:
• first placing said sample on said stage for supporting a sample with the back side thereof in contact with said stage and obtaining a first set of data, and second flipping said sample so that it's surface is in contact with said stage and obtaining a second set of data;
• and
• by first placing the north pole of a permanent magnet near to the sample and obtaining a first set of data, and second placing the south pole of the same or another magnet so that it is near the sample and obtaining a second set of data;
• followed by subtracting the first from the second or the second from the first obtained set of data for each selection from the group of elements consisting of at least one selection from the group consisting of M12, M13, M23, or at least one selection from the group of elements consisting of M12, M13, M33;
• followed by dividing said result(s) by M11, before, from said anisotropic value(s), determining at least one of the free charge carrier concentration and/or mobility.

An ellipsometer system comprising:

• a polarization state generator;
• a stage for supporting a sample, said stage having a substantially flat surface;
• and
• a polarization state detector;
• such that in use said polarization state generator directs a polarized beam of electromagnetic radiation to interact with a sample on said stage for supporting a sample, which after said interaction presents as a beam of electromagnetic radiation that enters said polarization state detector, that in response produces sample characterizing data;
• said ellipsometer system being distinguished in that said stage for supporting a sample is functionally a part of a resonate cavity that directs electromagnetic radiation that passes through a transparent or semi-transparent sample supported upon said stage having a substantially flat surface to be reflected back into said transparent or semi-transparent sample, such that when sample characterizing data is being accumulated by said polarization state detector, it is enhanced over what it would be otherwise as a result of coherent interaction in said transparent or semi-transparent sample between electromagnetic radiation incident thereupon provided by said polarization state generator, and electromagnetic radiation that reflects back into said transparent or semi-transparent sample as a result of said resonance effect, a resulting coherent combination of said two identified contributions of electromagnetic radiation in said sample then comprising said beam that enters said polarization state detector;
• said system being characterized by the presence of a magnet casing plate, such that in use a magnet is secured thereto in a manner such that a magnetic field directed other than parallel thereto at the sample surface is presented to said sample.

A method of evaluating at least some of free charge carrier longitudinal and/or transversal effective masses and/or concentration and/or mobility and/or free charge carrier type in a sample having a back side and a surface, said sample being transparent or semi-transparent or approaching substantially opaque beyond a distance from a surface thereinto at wavelength(s) utilized, said method comprising the steps of:

• a) providing an ellipsometer comprising:
• a source of a beam of electromagnetic radiation characterized by at least one wavelength in a selection from the group consisting of the:
• Visual;
• MIR;
• FIR;
• and
• THz ranges,
• a polarizer;
• a stage for supporting a sample, said stage comprising an adjustable surface that is capable of orienting a sample placed thereupon via adjustment of at least one selection from the group consisting of:
• stage tip, stage tilt and rotation thereof about an axis projecting substantially normal to said stage surface, to desired value(s);
• an analyzer;
• and
• a detector of relevant electromagnetic radiation wavelengths;
• and
• further providing a source of a magnetic field;
• b) placing a sample on said stage and adjusting said stage so that stage tip and/or stage tilt and/or rotation thereof about an axis projecting substantially normal to said stage surface are set to desired values, and so that the source of a magnetic field provides a magnetic field other than parallel thereto at said surface of said sample;
• c) while applying the source of a magnetic field to apply a selected magnitude magnetic field other than parallel thereto at the surface of said sample, causing said source of electromagnetic radiation to provide a beam of electromagnetic radiation of a desired wavelength which is caused to pass through said polarizer and assume a polarization state, interact with said sample, pass through said analyzer and enter said detector which detector produces sample characterizing data;
• d) from data accumulated by said detector with the system adjusted as described in steps b) and c), evaluating anisotropic values for at least a partial Jones or Mueller Matrix;
• and
• e) from said anisotropic values for said at least a partial Jones or Mueller Matrix determining at least one of the free charge carrier longitudinal and/or transversal effective masses, and/or concentration, and/or mobility and/or type.

A method of determining at least some of free charge carrier concentration and/or mobility in a sample, said sample having a back side and a surface and being transparent or semi-transparent or substantially opaque beyond some distance thereinto from a surface thereof thereinto at wavelength(s) utilized, said method comprising the steps of:

• a) providing an ellipsometer comprising:
• a source of a beam of electromagnetic radiation characterized by at least one wavelength in a selection from the group consisting of the:
• Visual;
• MIR;
• FIR;
• and
• THz ranges;
• a polarizer;
• a stage for supporting a sample, said stage comprising an adjustable surface that is capable of orienting a surface of a sample placed thereupon via adjustment of at least one selection from the group consisting of:
• stage tip, stage tilt and rotation thereof about an axis projecting substantially normal to said stage surface, to desired value(s);
• an analyzer;
• and
• a detector of relevant electromagnetic radiation wavelengths;
• further providing a source of a magnetic field;
• b) placing a sample on said stage and adjusting said stage so that stage tip and/or stage tilt and/or rotation thereof about an axis projecting substantially normal to said stage surface are set to desired values, and so that the source of a magnetic field provides a magnetic field other than parallel thereto at said surface of said sample;
• c) while applying the source of a magnetic field to apply a selected magnitude magnetic field other than parallel thereto at the surface of said sample, causing said source of electromagnetic radiation to provide a beam of electromagnetic radiation comprising at least one wavelength of a substantially exact multiple of a an optical path length in said sample, and which beam is caused to pass through said polarizer and assume a polarization state, interact with said sample, pass through said analyzer and enter said detector, which detector produces sample characterizing data;
• d) from data accumulated by said detector with the system adjusted as described in steps b) and c), evaluating anisotropic values for at least a partial Jones or Mueller Matrix;
• and
• e) from said anisotropic values for said at least a partial Jones or Mueller Matrix determining at least one of the free charge carrier concentration and/or mobility by direct calculation rather than by a mathematical regression procedure.

A method of determining at least one of free charge carrier concentration and/or mobility in a sample, said sample having a back side and a surface and being transparent or semi-transparent at wavelength(s) utilized, said method comprising the steps of:

• a) providing an ellipsometer comprising:
• a source of a beam of electromagnetic radiation characterized by at least one wavelength selected from the group consisting of:
• Visual;
• MIR;
• FIR;
• and
• THz ranges;
• a polarizer;
• a stage for supporting a sample;
• an analyzer;
• and
• a detector;
• b) placing a sample on said stage and adjusting said stage so that stage tip and/or stage tilt and/or rotation thereof about an axis projecting substantially normal to said stage surface are set to desired values, and so that the source of a magnetic field provides a magnetic field other than parallel thereto at said surface of said sample, and/or adjusting positioning of the source of a magnetic field which is oriented to provide a magnetic field other than parallel thereto at said surface of said sample, to achieve a desired value of magnetic field at said sample surface;
• c) while applying the source of a magnetic field to provide a selected magnitude magnetic field other than parallel thereto at the surface of said sample, causing said source of electromagnetic radiation to provide a beam of electromagnetic radiation which is caused to pass through said polarizer and assume a polarization state, interact with said sample, pass through said analyzer and enter said detector, which detector produces sample characterizing data;
• d) from data accumulated by said detector with the system adjusted as described in steps b) and c), evaluating anisotropic values for at least a partial Jones or Mueller Matrix;
• and
• e) from said values for said at least a partial Jones or Mueller Matrix determining at least one of the free charge carrier concentration and/or mobility.

A method of enhancing the capability of determining at least one of free charge carrier concentration and/or mobility in a sample having a back side and a surface, said sample being transparent or semi-transparent at wavelength(s) utilized, said method comprising the steps of:

• a) providing an ellipsometer comprising:
• a source of a beam of electromagnetic radiation characterized by at least one wavelength in a selection from the group consisting of the:
• Visual;
• MIR;
• FIR;
• and
• THz;
• ranges;
• a polarizer;
• a stage for supporting a sample;
• an analyzer;
• and
• a detector;
• and a source of a magnetic field having a surface associated therewith and which is oriented to provide a magnetic field other than parallel thereto at said surface of said sample;
• b) placing a sample on said stage and adjusting said stage so that stage tip and/or stage tilt and/or rotation thereof about an axis projecting substantially normal to said stage surface are set to desired values, and so that the source of a magnetic field provides a magnetic field other than parallel thereto at said surface of said sample, and/or further adjusting the source of a magnetic field so that it is oriented to provide a magnetic field other than parallel thereto at said surface of said sample of a desired value;
• c) while applying the source of a magnetic field to apply a magnetic field other than parallel thereto at the surface of said sample or a desired value, causing said source of electromagnetic radiation to provide a beam of electromagnetic radiation comprising at least one wavelength which is substantially a multiple of an optical path length in said sample, which beam is caused to pass through said polarizer and assume a polarization state, interact with said sample, pass through said analyzer and enter said detector, which detector produces sample characterizing data;
• d) from data accumulated by said detector with the system adjusted as described in steps b) and c), evaluating anisotropic values for at least a partial Jones or Mueller Matrix;
• and
• e) from said values for said at least a partial Jones or Mueller Matrix directly determining at least one of the free charge carrier concentration and/or mobility;
• said method being distinguished in that, while data is being accumulated by said detector, a gap is caused to exist between at least one selection from the group consisting of:
• 1) said sample backside and the sample supporting stage;
• and
• 2) said sample supporting stage and said surface associated with said source of a magnetic field which is oriented to provide a magnetic field other than parallel thereto at said surface of said sample of a desired value;
• such that a cavity is formed in which at least some electromagnetic radiation in the beam thereof directed at said sample by said source of a beam of electromagnetic radiation passes through said sample, and is coherently reflected back thereinto by said surface associated with said source of a magnetic field, thereby enhancing the signal entering the detector.