Surface observing apparatus and method

A surface microscopy method, comprising the steps of:

• scanning a surface of a specimen with a probe in repulsive force mode by relatively moving said probe and said specimen;
• selectively stopping movement of said probe or said specimen at every pixel on said surface of said specimen;
• moving said probe or said specimen so that a distance between said probe and said surface of said specimen changes;
• detecting a force and force gradient between said probe and said surface of said specimen at two different positions thereby measuring a profile of said surface of said specimen and the gradient distribution of forces;
• and
• repeating the above-mentioned steps for each of the pixels for said surface structure of said specimen and said force gradient distributions of said specimen.

A surface observing apparatus, comprising:

• a probe;
• a cantilever carrying said probe;
• probe moving means for moving said probe in a plane extending substantially in parallel with the surface of a specimen and in a plane extending substantially perpendicular to the surface of said specimen;
• specimen moving means for moving said specimen in a plane extending substantially in parallel to the surface of said specimen so as to effect a scanning of said surface by said probe;
• and
• means for detecting a force gradient between said probe and said surface of said specimen at two different positions and for measuring a profile of said surface of said specimen, wherein a force gradient distribution is detected by positioning said probe at said two different positions in a direction perpendicular to said surface of said specimen.

A surface observing apparatus, comprising:

• a probe in the form of a spin polarized ferromagnetic needle;
• a deformable cantilever for holding said probe;
• means for causing said probe to scan a surface of a specimen to be observed along said surface;
• means for detecting a DC component of displacement or deflection of said cantilever;
• means for controlling a position of said probe or alternatively a position of said specimen so that the DC component of displacement or deflection of said cantilever is maintained constant;
• means for detecting a current flowing between said probe and said specimen;
• means for changing a spin polarization ratio of said ferromagnetic probe needle with a predetermined frequency;
• and
• means for detecting a current flowing between said specimen and said probe needle and with said predetermined frequency.

A surface observing apparatus, comprising:

• a probe;
• a deformable cantilever holding said probe;
• means for scanning a surface of a specimen for observation with said probe along said specimen surface;
• means for vibrating said cantilever;
• a positive feedback loop, including:
• means for detecting displacement or deflection of said cantilever,
• a feedback circuit for feeding back a signal corresponding to the frequency of an output of said detecting means to said vibrating means, and
• a phased locked loop which includes said positive feedback loop and further includes:
• a reference frequency generator for generating a desired frequency,
• a phase comparator for detecting a phase difference between the desired frequency and the signal corresponding to the frequency of the output of said detecting means, and
• means for adjusting a relative position between said probe and said surface of said specimen so that the frequency of the output of said detecting means is changed;
• reference signal generating means for generating a signal of a constant frequency and phase;
• means for detecting a phase difference between the output signal of said reference signal generating means and the output signal of said cantilever displacement or deflection detecting means;
• and
• control means for controlling a distance between a tip of said probe and said specimen surface so that the phase difference between the output signal of said reference signal generator and the output signal of said cantilever displacement detecting means approaches a phase difference of zero.