MEASUREMENT OF REDUCED SURFACE-BARRIER HEIGHT IN SULFUR PASSIVATED INP AND GAAS USING RAMAN-SPECTROSCOPY

Surface defect passivation of n-type (100) InP and GaAs surfaces have been achieved using (NH4)2S and P2S5 solutions. The reduction in surface band bending as a result of the sulfide treatment is determined using Raman scattering measurements. Following the chemical treatment, the InP surfaces exhibit reduced surface energy barrier heights in the range of 0.27-0.32 eV For GaAs, passivation with sulfide solutions results in surface energy barriers in the range 0.43-0.47 eV However, the samples that were deep-etched in HCL based etchant exhibit values as low as 0.11 eV There is no noticeable difference in the observed barrier heights due to (NH4)2S and P2S5 solutions, with both the chemicals appearing to be equally effective for passivation.