The GaAs metal-semiconductor-metal (MSM) device is a very useful planar and
monolithic-microwave integrated-circuit compatible photodetector and elect
ron-detector. As a photodetector, the MSM has been used for many applicatio
ns in the past, however, in this paper we demonstrate its usefulness as an
electron-beam detector as well. We present here a comprehensive analysis of
the primary detection mechanism (electric field enhanced collection of gen
erated electrons) as well as a newly identified secondary mechanism. This n
ew mechanism is characterized by a high detection gain, but low speed. Expe
rimental results are presented to verify the analysis, and possible applica
tions are suggested by utilizing each one of the two detection mechanisms.