The photoluminescence characteristics of GaAs surface by plasma treatment

In this study, the effect of plasma treatment on the photoluminescence (PL) of GaAs surface by Ar, O2 and Ar/O2 mixed plasma was investigated. The influence of process parameters, such as chamber pressure, gas flow rate, mixture gas ratio and RF power, on the PL characteristics of GaAs surface were discussed. Experimental results indicated that the PL intensity of the samples treated by Ar and O2 plasma degraded significantly with increasing RF power. With the increase of chamber pressure, the degradation of PL intensity was improved. The PL intensity of samples treated by O2 plasma under high chamber pressure exhibited a lower degradation. Moreover, the PL intensity degradation weakened first and then became significant with the increase of O2 flow rate. Under Ar and O2 mixed plasma treatment, the PL intensity degradation also tended to increase as the Ar/O2 ratio gas became higher. These results suggest that chamber pressure, gas flow rate, and RF power have strong influences on the surface properties of the plasma-treated GaAs, and PL degradation caused by plasma process can be well weakened, or even eliminated by the optimization of process parameters. A decreasing RMS roughness with increasing chamber pressure is observed, which is consistent with the PL measurement results.