BALLISTIC-ELECTRON-EMISSION MICROSCOPY TO PROBE INTERFACES OF SIMPLE DEVICE STRUCTURES

Ballistic electron emission microscopy (BEEM) is a powerful new techni que capable of probing the electrical barriers at semiconductor interf aces on a microscopic scale. It is also very useful for probing the de tails of the semiconductor band structures, particularly the positions of the upper valleys in the conduction band. Over the past two years we have used BEEM to investigate both metal-semiconductor contacts and heterojunction interfaces, and we report here some of the data obtain ed during the investigation. The Au/GaAs and Au/InGaAs/AlGaAs systems have been chosen as a vehicle to demonstrate both the power of the tec hnique and its limitations.