An atomic-scale view of semiconductor heterostructures using scanning tunneling microscopy

As the characteristic dimensions of advanced semiconductor devices approach the nanometer scale, characterization at or near the atomic scale is emerging as an essential aspect of materials and device engineering. We have used cross-sectional scanning tunneling microscopy to elucidate atomic-scale structure, and its correlation with material properties and device behavior, in a variety of III-V semiconductor heterostructures. A few representative examples of our recent work in this area are presented, with emphasis on quantitative characterization of atomic-scale interface roughness and its correlation with transport properties in InAs/Ga_1-xIn_xSb superlattices, and on atomic-scale compositional structure of alloys in InAs_xP _1-xInP and InAs_1-x/InAs_1-ySb_y heterostructures