Afm-coupled microscale radiofrequency probe for magnetic resonance imaging and spectroscopy

A system for micro-scale spectroscopy, the system comprising:

• a probe, the probe comprising:
• a beam having a distal end, a proximal end, a top surface and a bottom surface, the beam being attached to an anchor at the proximal end and further comprising a tip extending substantially perpendicular from the bottom surface at or near the distal end,
• a coil having at least one turn mounted to the top surface of the beam at or near the distal end opposite the tip, wherein the coil is capable of both transmitting and sensing electromagnetic radiation,
• at least two leads electrically connected to the coil,
• at least two coil contacts electrically connected to the at least two leads and disposed adjacent to the anchor;
• and
• a spectrometer electrically connected to the at least two coil contacts, the spectrometer capable of transmitting electromagnetic radiation via the coil and of performing a Fourier analysis of the electromagnetic radiation sensed by the coil;
• wherein the probe is capable of atomic force microscopy via deflection of the beam when the tip is contacted with a sample;
• and
• wherein the probe, when positioned within a magnetic field, is capable of nuclear magnetic resonant spectroscopy by transmission to and reception of electromagnetic radiation from the sample via the coil.

A method of using a AFM/NMR probe, the method comprising the steps of:

• placing a sample to be analyzed into a magnetic field;
• introducing a probe into proximity with the sample, the probe comprising:
• a beam having a distal end, a proximal end, atop surface and a bottom surface, the beam being attached to an anchor at the proximal end and further comprising a tip extending substantially perpendicular from the bottom surface at or near the distal end, and
• a coil having at least one turn mounted to the top surface of the beam at or near the distal end opposite the tip, wherein the coil is capable of both transmitting and sensing electromagnetic radiation;
• moving the probe until the tip contacts a surface of the sample, thereby ensuring close proximity between the coil and the sample;
• scanning the surface with the tip by moving the tip across the surface of the sample;
• while the tip is in contact with the surface of the sample, generating an electromagnetic field via the coil, the electromagnetic field being localized to the sample;
• waiting a period of time for nuclei within the sample to generate a resonant signal in response to the electromagnetic field generated from the coil;
• and
• acquiring the resonant signal generated by the nuclei within the sample via the coil.

A method of fabricating the a AFM/NMR probe, the method comprising the steps of:

• providing a beam, the beam comprising:
• a beam having a distal end, a proximal end, atop surface and a bottom surface, the beam being attached to an anchor at the proximal end and further comprising a tip extending substantially perpendicular from the bottom surface at or near the distal end;
• applying a first insulation layer of insulating material on the top surface of the beam;
• applying a first conductive layer of electrically conductive material to the first insulation layer on the beam;
• and
• etching the first conductive layer to define a coil at or near the distal end opposite the tip, at least one lead adjacent the coil, and at least one contact adjacent the at least one lead at or near the proximal end, wherein the coil, at least one lead, and at least one contact are electrically connected.

A method of fabricating the a AFM/NMR probe, the method comprising the steps of:

• forming a wafer having a top surface and a bottom surface with a first oxide layer thereon;
• etching the wafer to form an trench in the top surface;
• applying a second oxide layer within the trench;
• further etching the coated opening to form a desired tip shape;
• depositing a structural layer to the top surface and into the trench to form a beam and a tip, wherein the beam defines a top surface, a bottom surface, a distal end, and a proximal end, and wherein the tip extends substantially perpendicular from the bottom surface at or near the distal end;
• depositing a first conductive layer on the top surface over the structural layer to form a coil and at least one lead adjacent the coil, wherein the coil includes one or more ends and is disposed at or near the distal end of the beam opposite the tip, and wherein the at least one lead extends to the proximal end of the beam;
• applying an insulation layer over the first conductive layer;
• etching the first insulation layer to form one or more passages to the at least one lead and one end of the coil;
• depositing a second conductive layer over the first insulation layer to form an electrical connection between one end of the coil and at least one lead via the one or more passages;
• applying a second insulation layer over the second conductive layer;
• applying a third oxide layer over the second insulation layer;
• dissolving a portion of the wafer surrounding the tip;
• and
• dissolving the second oxide layer from area surrounding the tip.