PASSIVATION OF SURFACE AND BULK DEFECTS IN P-GASB BY HYDROGENATED AMORPHOUS-SILICON TREATMENT

Passivation of point and extended defects in GaSb has been observed as a result of hydrogenated amorphous silicon (a-Si:H) treatment by the glow discharge technique. Cathodoluminescence (CL) images recorded at various depths in the samples clearly show passivation of defects on t he surface as well as in the bulk region. The passivation of various r ecombination centers in the bulk is attributed to the formation of hyd rogen-impurity complexes by diffusion of hydrogen ions from the plasma a-Si:H acts as a protective cap layer and prevents surface degradatio n which is usually encountered by bare exposure to hydrogen plasma. An enhancement in luminescence intensity up to 20 times is seen due to t he passivation of nonradiative recombination centers. The passivation efficiency is found to improve with an increase in a-Si:H deposition t emperature. The relative passivation efficiency of donors and acceptor s by hydrogen in undoped and Te-compensated p-GaSb has been evaluated by CL and by the temperature dependence of photoluminescence intensiti es. Most notably, effective passivation of minority dopants in telluri um compensated p-GaSb is evidenced for the first time. (C) 1996 Americ an Institute of Physics.