MEASUREMENTS OF LOCAL STRAIN VARIATION IN SI1-XGEX SI HETEROSTRUCTURES/

The energy splitting of the conduction-band minimum of Si1-xGex due to strain has been directly measured by the application of ballistic-ele ctron-emission microscope (BEEM) spectroscopy to Ag/Si1-xGex structure s. Experimental values for this conduction-band splitting agree well w ith calculations. For Au/Si1-xGex, however, heterogeneity in the strai n of the Si1-xGex layer is introduced by deposition of the Au. This va riation is attributed to species interdiffusion, which produces a roug h Si1-xGex surface. Preliminary modeling indicates that the observed r oughness is consistent with the strain variation measured by BEEM. (C) 1995 American Vacuum Society.