Method and apparatus for measuring mechanical and electrical characteristics of a surface using electrostatic force modulation microscopy which operates in contact mode

A microscope arrangement comprising:

• a tip contacting a sample;
• a voltage source coupled to said tip for applying a voltage between said tip and said sample, wherein said voltage has a direct current component and an alternating current component of an applied frequency and said voltage source comprises a direct current voltage source and an alternating current voltage source;
• a tip vibration detector for detecting a vibration of said tip, wherein said vibration of said tip comprises a component having a frequency approximately equal to said applied frequency;
• a lock-in amplifier configured to isolate said component;
• and
• a feedback loop coupled to said lock-in amplifier;
• wherein said direct current voltage source further comprises an adjustable direct current voltage source, and said feedback loop is coupled to said adjustable direct current voltage source.

A method of observing a sample comprising:

• maintaining a tip in contact with said sample;
• while maintaining, applying a voltage between said tip and said sample to generate an electrostatic force wherein said voltage has at least an alternating current component;
• mechanically deforming said sample primarily by application of said electrostatic force;
• and
• measuring a signal related to deformation of said sample.

A microscope comprising:

• a tip contacting a sample, said tip having a vibration;
• a cantilever supporting said tip at a free end of said cantilever;
• a cantilever support supporting a fixed end of said cantilever;
• a reflector located on said cantilever;
• a laser source aimed at said reflector;
• a laser detector configured to receive laser light emitted from said laser source that reflect from said reflector;
• a first voltage source coupled to said tip for applying a first voltage to said tip, said first voltage source comprising:
• an alternating current voltage source for applying to said tip an alternating voltage having a frequency on said tip, said vibration having a first component having approximately said frequency and a second component having approximately twice said frequency;
• and
• an adjustable direct current voltage source, wherein said first voltage has an ac component and a dc component;
• a second voltage source for grounding said sample;
• a first lock-in amplifier configured to isolate said first component;
• a second lock-in amplifier configured to isolate said second component;
• and
• a feedback loop coupled to said first lock-in amplifier and to said adjustable direct current voltage source.

A microscope arrangement comprising:

• a tip contacting a sample;
• an adjustable voltage source coupled to said tip for applying a voltage to said tip wherein said voltage has at least an alternating current (AC) component;
• a feedback loop coupled to said adjustable voltage source;
• and
• a lock-in amplifier coupled to receive a signal from said tip.

A method of observing a sample comprising:

• maintaining a tip in contact with said sample;
• while maintaining, applying a voltage between said tip and said sample to generate an electrostatic force that deforms said sample wherein said voltage has at least an alternating current component;
• and
• while applying, measuring a signal related to the deformation due to said electrostatic force.

A microscope arrangement comprising:

• a non-piezoelectric sample;
• a tip contacting said sample;
• an alternating current voltage source coupled to said tip;
• and
• a lock-in amplifier coupled to receive a signal from said tip.

A method of measuring a property comprising:

• providing a non-piezoelectric sample;
• maintaining a tip in contact with said sample;
• while maintaining, applying a voltage between said tip and said sample wherein said voltage has at least an alternating current component;
• and
• measuring a signal related to deformation of said sample.

A method of observing a sample comprising:

• maintaining a tip in contact with said sample;
• while maintaining, applying a voltage between said tip and said sample wherein said voltage has at least an alternating current component;
• while applying, measuring a signal from said tip;
• and
• charging said voltage based on said signal.

A microscope arrangement comprising:

• a tip contacting a sample;
• first means coupled to said tip for applying a voltage to said tip wherein said voltage has at least an alternating current (AC) component;
• and
• second means coupled to said tip for receiving a signal and amplifying a portion of said signal wherein said first means generates an electrostatic force on said tip to cause deformation of said sample.