Surface Passivation of Gallium Arsenide

摘要

The surface passivation of Si doped (100) n-type gallium arsenide (GaAs) by chemical treatment with phosphoric acid (H3P04), phosphorus trichloride (PCl3), and sodium sulfide (Na2S.9H2O) was investigated using room temperature photoluminescence (PL) and a capacitance-voltage (C-V) and current-voltage (I-V) profiler. After passivation, the 300K PL increased for all three treatments. Best results obtained showed improvements of 1.4, 3.5 and 5.3 times greater of PL efficiency for H3PO4, PCl3 and Na2S, respectively, over unpassivated samples that were only cleaned and etched. Samples that were cleaned, etched and washed with de-ionized 18 Mohm, 5 ppm O2 content water showed about the same PL increase as the H3PO4 passivation. Capacitance-voltage and I-V profile curves showed the removal of the surface oxide hysteresis with the PCl3 passivated samples; however, re-oxidation seems to take longer than normal and to be confined to the passivation layer. Theses. (mjm)