Cathodoluminescence investigations of RIE-induced defects in InP

Cathodoluminescence (CL) measurements have been performed to characterize defects in InP created by reactive ion etching (RIE) in a CH₄/H₂/Ar plasma. Etching of semi-insulating InP:Fe leads to an increase of CL intensity. After etching of undoped, n-type InP a reduction of band-edge as well as band-acceptor/donor-acceptor-pair emission intensity is detected. No additional emission lines due to etching-induced defects have been detected in the spectral range examined. After a few minutes of electron beam injection the band-edge luminescence recovers to its initial value. Using donor-bound exciton emission, which is especially affected by RIE, mapping of these defects is possible, showing homogeneous defect distribution. In conjunction with other measurements (conductivity, photoluminescence, electron-beam-induced current, Raman scattering, Auger electron spectroscopy depth profiling) these results indicate a nonradiative, donor-like defect created by RIE.