Low damage and low surface roughness GaInP etching in Cl[sub 2]/Ar electron cyclotron resonance process

Abstract

Electron cyclotron resonance Cl2/Ar plasma etching characterization was performed to obtain low damage and low surface roughness conditions for GaInP lattice matched to GaAs. Micro-Raman spectroscopy, atomic force microscopy (AFM) and surface profiling were used to characterize the near-surface quality and etch rate of GaInP. The results show that near-surface damage increases with dc self-bias voltage in both Ar and Cl2/Ar plasmas. Etching in pure Ar plasma results in significant increase in the transverse-optic (TO) intensity at high dc self-bias voltage of 50 and 70 V, with the longitudinal-optic (LO) peaks downshifted in frequency. A normalized LO/TO intensity was quantified in this study to represent the combined effect of increase in TO intensity and slight decrease in LO intensity. In the case of Cl2/Ar plasma, substantial shifting of the GaP-like LO peak position to lower frequency was observed at dc self-bias voltage of 70 V at 120 °C with increase in the TO peak intensity. In addition, the decre...