STUDY OF DEFECTS GENERATED FROM A NITRIDATION OF GAAS SURFACE

Defects studies have been performed on nitrided GaAs with deep level t ransient spectroscopy (DLTS) and photoluminescence (PL) measurements. Thin nitrided GaAs was formed by the irradiation of nitrogen electron cyclotron resonance (ECR) plasma at various substrate temperatures ran ging from room temperature to 600 degrees C, Two electron deep levels, N1 (E-c - 0.13 eV) and N2 (E-c - 0.58 eV), related to thermal assiste d nitridation induced defects were observed in the GaAs nitrided at 60 0 degrees C while no additional point defects were generated at nitrid ation temperatures up to 450 degrees C, Several deep levels such as N1 and N2 are also found to be remarkably reduced by rapid thermal annea ling at 750 degrees C without any significant surface degradations. Fr om analysis of the trap concentration and its variations with anneal t emperature, the nitridation temperature of 450 degrees C followed by r apid thermal annealing at around 750 degrees C is found to be the opti mum condition for nitridation without the generation of thermally assi sted nitrogen plasma-induced defects. The V-As related complex and low energy ion beam induced defects are discussed as the probable sources for the N1 and N2 level defects, respectively.