BALLISTIC-ELECTRON-EMISSION MICROSCOPY OF STRAINED AND RELAXED IN0.35GA0.65AS ALAS INTERFACES/

We report here our investigations upon both strained and relaxed In0.3 5Ga0.65As/AlAs interfaces using the ballistic electron emission micros copy (BEEM) and current-voltage (I-V) techniques. Six samples, of diff erent InGaAs thickness and doping density, were grown by molecular bea m epitaxy and were designed to assess the importance of strain relaxat ion/dislocations in barrier formation. In the heavily dislocated situa tion (thicker InGaAs film) the obtained barrier most likely resulted f rom Fermi level pinning. However, this was obviously not the case for both the pseudomorphic and lightly dislocated situations (thinner InGa As films). It was also noted that the measured barriers varied more wi dely over space in the lightly dislocated layer than that in the pseud omorphic case and that the simultaneously obtained topographic and BEE M images points to a better interface in the pseudomorphic layer than that in the partially relaxed situation. (C) 1995 American Vacuum Soci ety.