Drain-current DLTS study of an GaAs/InP MESFET

Fast GaAs Metal-Semiconductor Field-Effect-Transistor (MESFET) on InP exhibiting promising performances comparable to those grown on GaAs subtrates have already been fabricated. The lattice mismatch of 4% between GaAs and InP did not preclude device fabrication, although the characterization of such materials has shown the existence of high dislocation density at the interface and a residual biaxial tensile strain due to the difference between the thermoelastic properties of the two materials. The above-mentioned growth difficulties can generate many defects, which are very detrimental for device application. In this context, we have investigated deep levels on Rapid Thermal Annealed (RTA) GaAs/InP MESFET by means of Drain-Current Deep-Level Transient Spectroscopy (CDLTS). In this study, we have revealed the absence of dislocation-generated-deep level, the formation of an apparent "hole-like" observed for the first time with an activation energy of 0.3 eV. On comparison with homo-epitaxial GaAs MESFET achieved under the same conditions, we note the absence of a deep level with an apparent activation energy of 0.4 eV. (C) 2000 Elsevier Science Ltd. All rights reserved.