Deep levels in Ti-doped GaAs epilayers grown on undoped GaAs 100/substrates

Deep-level transient spectroscopy DLTS.measurements have been carried out to investigate the deep levels existing in Ti-doped GaAs epilayer grown on GaAs substrates by liquid phase epitaxy. While one hole-trap was observed for the undoped GaAs epilayer, two new traps appeared for the Ti-doped GaAs epilayers. The trap activation energies and the capture cross-sections for the two traps appearing in the Ti-doped GaAs epilayers are 0.2 eV and 3.5=10y17 cm2 for the Ti2qrTi3q peak, and 0.93 eV and 3.11=10y15 cm2 for the Ti3qrTi4q peak. These results indicate that the Ti-doped GaAs epilayer forms new defect levels and that the levels restrict the activation of transformed impurities. Furthermore, the present results can help improve the understanding of the applications of Ti-doped GaAs epilayers in electronic devices. q1999 Published by Elsevier Science B.V. All rights reserved