The effect of electron beam irradiation damage upon a pseudomorphic modulation-doped 2-dimensional hole gas was investigated. It was found that the material properties were not significantly affected by typical treatments which involved electron energies of 40keV and doses of 2C/m2. Upon using 300keV electrons, the resistivity of the material increased as the electron dose was increased. Upon using 100keV or higher irradiation energies, the material became more resistive as the energy was increased. The 2-dimensional hole gas material became highly resistive at low temperatures, and froze out at temperatures of between 20 and 30K. Annealing (400 to 500C) of 40keV-irradiated (2C/m2) samples could restore the resistivity of the material, at 300K, to the pre-irradiation value. The large increase in resistivity which occurred at annealing temperatures above 500C suggested that irradiation produced a significant number of defects which accelerated the relaxation of strained Si0.87Ge0.13.

D.J.Paul, J.M.Ryan, M.Pepper, A.N.Broers, T.E.Whall, J.M.Fernández, B.A.Joyce: Journal of Vacuum Science and Technology B, 1996, 14[6], 3834-8