REDUCTION OF RESIDUAL OXYGEN INCORPORATION AND DEEP LEVELS BY SUBSTRATE MISORIENTATION IN INGAALP ALLOYS

Effects of substrate misorientation on deep levels and on oxygen incor poration have been investigated in undoped In0.5(Ga1-xAlx)(0.5P(x=0.0- 1.0) grown be metalorganic chemical vapor deposition (MOCVD). Deep-lev el transient spectroscopy (DLTS) measurements have revealed three deep levels (E(DLTS) = 0.42 eV, 0.64 eV and almost-equal-to 1.0 eV). The c oncentrations of the deeper two deep levels increased with increasing x, and they were drastically reduced by using (100) substrate 15-degre es off tilted towards [011]. The residual oxygen concentration was als o reduced by using the off-axis substrate. It has been shown that the above-mentioned two deep levels are related to oxygen, and have deteri ous effects on the luminescent properties of InGaAlP alloys.