PHOTOLUMINESCENCE CHARACTERIZATION OF INP SURFACE REACTIVE ION ETCHED BY A GAS-MIXTURE OF ETHANE AND HYDROGEN

InP crystals were etched by reactive ion etching (RIE) with gas mixture of ethane and hydrogen (C2H6/H2), and etching damages were characterized by photoluminescence (PL) measurements of near-edge and defect-related emissions. Near-edge PL emission intensities after RIE were equal to or larger than those before RIE, except for the samples etched for 50 min. The damage introduced by RIE was restricted to the very-near-surface region which can be removed by HF treatment. The peak energy of defect-related 1.1 eV deep emission bands shifted toward the lower-energy side for the crystals with etching damages at the surface. The peak shift is attributable to the increase of defect complexes such as P-vacancy-P-interstitial or P-vacancy-In-vacancy.