Comparison between process-induced defects in n-GaAs exposed to hydrogen and argon plasmas

We present deep levels introduced in n-GaAs during plasma irradiation with two kinds of gases: H, and Ar. The annealing behavior of the induced defects under applied bias was investigated to understand the nature and the origin of these induced defects. The dominant donor-type defect (EA3) was detected in the DLTS spectra slightly below 250 K both in hydrogen or argon gas species. The second highest peak was observed around 150 K in the DLTS spectra ‘apparently’ for all samples. A metastable defect (M3/M4), one of the ‘150 K peak’ defects, was induced upon hydrogen-plasma exposure only in the crystals with the EL2 defect in the as-grown state.