Defect states in hydrogenated GaAs

Abstract

The properties of hydrogen in GaAs material has been investigated. The various states of hydrogen are detailed, together with incorporation of hydrogn atom with shallow and deep levels defects that passivate their electrical activity. The passivation and dissociation process of the hydrogen-Si donor complex in plasma-hydrogenated GaAs was presented. Also, it is demonstrated that atomic hydrogen drifts as a negatevely charged state in n-type GaAs and the high-electric field strongly affects the dissociation of the hydrogen-donor complex. During reversebias anneal experiments on the Schottky diode, it is confirmed that a negatively charged hydrogen is accelerated out of the high-field region and that there is a dissociation frequency region independet of the anneal temperature. In the dissociation frequency region dependent on the anneal temperature, the first-order kinetics gives rise to the dissociation energy for the release of the hydrogen-Si donor complex. The dissoiction energies are dependent on the applied bias voltage and are in the ranges of 1.79 to 1.1 eV. New metastable behavior of deep level defects is found in hydrogenated GaAs doped with Si. A deep level defect at 0.60 eV below the conduction band minimum($E_c$) is generated during hydrogenation and shows metastable behavior for the $E_c$-0.42eV trap. Thermal annealing experiments under the biased and the unbiased conditions confirm that during hydrogcnation the 0.60eV trap is generated, as a metastable defect for the native defect at 0.42 eV, and the complete passivation of the 0.42 or the 0.33 eV trap during hydrogenation is due to passivation of the trap by hydrogen atom, forming hydrogen-defect complex. The first order kinetics permits a precise estimate of the formation and annealing frequencies $\nu\,_f$ and $\nu\,_a$ of the hydrogen-defect pair. The temperature dependent values of $\nu\,_a$ for the 0.60 eV trap satisfy the relation $\nu\,_a=0.82\times1013$ exp((-1.61$\pm$0.04 eV)/kT) S-1. It...