An experimental study of the reactive ion etching (RIE) of GaP using BCl3 plasma processing

A detailed study of the reactive ion etching (RIE) of GaP, through BCl3 based plasma processing is reported. We discuss the effects on the etch rate through the studies of RF power, reactant and carrier gas (Ar) flow and chamber pressure. Atomic force microscopy (AFM) characterization, along with photoluminescence (PL) spectroscopy, is used to investigate the surface quality and correlate the material damage. Compared to previous dry etching studies, we find that the etching rate is enhanced to 850 nm/min with slight increase in surface roughness. PL spectroscopy indicates a progressive degradation of the surface quality with increased RF power, which is not due to increased surface roughness but presumably due to either a change of the surface state density or depletion layer thickness in GaP.