HYDROGEN DIFFUSION AND ACCEPTOR PASSIVATION IN P-TYPE GAAS

Deuterium diffusion profiles in GaAs doped with different acceptors of group II (Mg,Zn,Cd) or group IV (C,Ge) have similar characteristics even though the neutralization of acceptors measured at 300 K is not always efficient. Conductivity and Hall measurements have been used to study the electrical characteristics of hydrogenated p-type GaAs epilayers. The temperature dependence of the free-carrier concentration and hole mobility before and after hydrogenation shows that the neutralization of acceptors by atomic hydrogen leads to the elimination of the shallow acceptor states. Infrared-absorption times associated with hydrogen-acceptor complexes are observed for all acceptors except magnesium. It is established that the microscopic structure of hydrogen-acceptor complexes depends on the acceptor site in the lattice.