A study of electrically active defects created in p-InP by CH4:H2 reactive ion etching

Abstract

The electrical effects of reactive ion etching (RIE) of p-InP by CH4:H2 are investigated. By using optical deep-level transient spectroscopy, several deep-level defects could be detected. The main defect (E3) is found to be a donor with an energy level at Ec−0.38 eV. From depth profiles of both the net acceptor concentration and this defect, it follows that after RIE, the E3 defects are passivated by hydrogen. Simultaneous passivation of both acceptors and donors on p-InP is reported. Subsequent rapid thermal annealing at increasing temperatures shows that the E3 defects are first depassivated and then annealed out. The change of the Schottky barrier height with the anneal temperature could be explained by Fermi-level pinning due to E3 and depinning either by its passivation for low enough temperatures or by its annealing out at higher temperatures. Some possibilities concerning the physical nature of E3 are discussed.