UNSTABLE DISPLACEMENT DEFECTS AND HYDROGEN TRAPPING IN GAAS

Defects produced by implantation of hydrogen into GaAs at 80 K have be en investigated. Upon implantation, a predominant absorption band at 2 029 cm(-1) for As-H centers is observed. A 10-cm(-1) full width at hal f maximum at 80 K for the band, and strong dependence of the frequency and bandwidth on measurement temperature, are indicative of bonding o f hydrogen at displacement defects within the lattice. Results from an nealing show loss of As-H centers between 180 and 250 K with an activa tion energy of 0.5+/-0.5 eV. Characteristics for As-H center annealing are compared to those reported previously for atomic displacement dis order in irradiated GaAs. Release of hydrogen from As-H bonds within t hermally unstable damage regions is suggested to explain the annealing loss of As-H centers. An increase in absorption by Ga-H centers upon loss of As-H centers is attributed to retrapping of hydrogen on Ga nei ghbors of V-As or on V-As-As-i pair defects.