Buried damaged layers in n-type material, which were created by implanting MeV Ar+ ions, were studied by using capacitance and current measurements, deep-level transient spectroscopy and constant capacitance time-analyzed transient spectroscopy. A new mid-gap acceptor level, which was responsible for carrier compensation, was isolated in samples that had been irradiated with doses to below the amorphization threshold. This defect level was shown to control hysteresis in capacitance-voltage characteristics, space-charge limited current conduction, and premature termination of emission transients. The emission energy of the defect was observed to be sensitive to the degree of disorder in the damaged layer. The latter was controlled by irradiation, and by relaxation-inducing heat treatment.

P.K.Giri, Y.N.Mohapatra: Applied Physics Letters, 1997, 71[12], 1682-4