Room temperature annealing of 5.48 MeV He induced defect in p+n and n+p grown by metal–organic chemical vapour deposition

Abstract

We have presented the results of the deep level transient spectroscopy (DLTS) study of the alpha-radiation-induced defects in n-type and p-InP crystals grown by low-pressure metal–organic chemical vapour deposition (LP-MOCVD). Irradiation of LP-MOCVD grown n-type InP by 5.48 MeV α-particles with a dose of 1.82×10 11 cm −2 results in five stable electron emitting levels, Eα3, Eα4, Eα5, Eα6, Eα7 and one room temperature unstable Eα8 level in the upper half of the band gap. The level Eα8 shows interesting behaviour during room temperature storage. It was found to anneal out with storage at room temperature with no change in other majority carrier levels. Detailed characteristics of these levels including thermal emission rates, carrier activation energies, capture cross-sections and their temperature dependence have been determined. In p-type InP three prominent majority carrier levels H3, H4 and H5 at energy positions E V+0.34 eV, E V+0.39 eV and E V+0.58 eV, respectively, and three minority carrier levels, 0.22, 0.29 and 0.35 eV below the conduction band edge are produced by irradiation. Some of the levels show interesting behaviour with room temperature storage and/or minority carrier injection. In particular, hole level H5, is produced in the majority carrier spectrum as a result of ∼40 h of room temperature (∼20°C) storage or more rapidly as a result of minority carrier injection. Minority carrier injection, on the other hand, triggers a rapid generation of H5 with a simultaneous decrease of H3 and H4. While H5 saturates with injection, H3 and H4 continue to decay after injection. A detailed comparison with the published results is presented. The origins of some levels in this study are also discussed.