PHASE-CONTROLLED SCANNING FORCE MICROSCOPE

A noncontact scanning force microscope employing a novel tip height co ntrol system using phase lock technology has been developed. An oscill ator using a cantilever as a mechanical resonator is used as a voltage controlled oscillator in a phase locked loop, and its output signal i s phase locked to a high-precision signal source. Its most remarkable feature is that this tip height control is unconditionally stable. Thu s, it was possible to realize the desired system response by adjusting the loop parameters. Its efficiency was demonstrated by imaging the s urface of a magneto-optical disk at the lowest tip height which was im possible to achieve with a conventional servo technology.