COMPOSITIONAL MAPPING OF SEMICONDUCTOR STRUCTURES BY FRICTION FORCE MICROSCOPY

Topographic and chemical mapping of materials at high resolution defin e the goals of a microscope. Force microscopy can provide methods for simultaneous topography and chemical characterization of materials. He re we describe the use of the atomic force microscope to map chemical variations of semiconductor samples. Chemical maps of semiconductor In P/InGaAs alloys have been determined with 3 nm spatial resolution whil e 10% changes in indium composition are resolved in InxGa1-xAs structu res. The present resolution is limited by the tip's curvature radius, cantilever lateral force constant, and the total applied force. Theore tical calculations predict lateral compositional resolutions of about 1 nm. (C) 1996 American Institute of Physics.