NEUTRON-IRRADIATION INDUCED DEFECTS IN LOW FREE-CARRIER CONCENTRATIONEPITAXIALLY GROWN N-GAAS

Deep level transient spectroscopy (DLTS) of low free carrier concentra tion n-GaAs revealed that high energy neutron irradiation introduced f ive electron traps, En1-En5, in molecular beam epitaxy (MBE) grown GaA s. Only four of these defects, En1, En2, En4 and En5 could be detected in irradiated GaAs grown by organo-metallic vapor phase epitaxy (OMVP E). The En1, En2 and En4 have similar DLTS ''signatures'' as the E1, E 2 and E3 defects created during high energy electron irradiation of Ga As. The DLTS ''signatures'' of En5 in the MBE and OMVPE samples are di fferent, and this difference is attributed to the presence of a near-s urface def ect which is more readily detectable in the MBE GaAs.