Material Property Measurements Using Multiple Frequency Atomic Force Microscopy

Abstract

Apparatus and techniques for extracting information carried in higher eigenmodes or harmonics of an oscillating cantilever or other oscillating sensors in atomic force microscopy and related MEMs work are described. Similar apparatus and techniques for extracting information using contact resonance with multiple excitation signals are also described.

What is claimed is: 
     
         1 . An atomic force microscope which processes a sample, comprising:
 an atomic force microscope cantilever which has a probe tip which moves relative to a surface of the sample;   a controller, controlling said cantilever by creating relative movement between the probe tip of the cantilever and the sample and measuring values used to control said cantilever, said controller using both first and second frequencies to cause said relative movement of the cantilever, where the first and second frequencies are different frequencies;   a mechanical actuator, driven by said controller for moving said cantilever, said mechanical actuator driven by said first frequency;   a magnetic field generator, creating a magnetic field at the sample, said controller using said second frequency to vary the magnetic field at the sample;   said controller using said first and second frequencies and a measured value indicative of said relative movement, to provide information indicative of a surface of the sample.   
     
     
         2 . The microscope as in  claim 1 , wherein said controller includes a lock—in amplifier locking in the first and second frequencies. 
     
     
         3 . The microscope as in  claim 1 , wherein said controller includes an RMS measurement circuit. 
     
     
         4 . The microscope as in  claim 1 , wherein the circuit part is a surface near the sample being measured. 
     
     
         5 . The microscope as in  claim 1 , wherein the circuit part is the sample being measured.