BALLISTIC-ELECTRON-EMISSION MICROSCOPY OF STRAINED SI1-XGEX LAYERS

Ballistic-electron-emission microscopy (BEEM) has been used to investi gate the effects of strain on Si1-xGex alloys. Lifting of the degenera cy of the conduction-band minimum of Si1-xGex due to lattice deformati on has been directly measured by application of BEEM spectroscopy to A g/Si structures. Experimental values for this conduction-band splittin g agree well with calculations. In addition, an unexpected heterogenei ty in the strain of the Si1-xGex layer is introduced by deposition of Au. This effect, not observed with Ag, is attributed to species interd iffusion and has important implications for metal-semiconductor device s based on pseudomorphic Si1-xGex/Si material systems.