Sb and Bi passivation effects on GaAs

Passivation effect, of Sb and Bi on GaAs were investigated. Sb and Bi were vacuum-evaporated on GaAs (100) substrates. The Au/Sb/GaAs and Au/Bi/GaAs S chottky diode samples showed improved current-density-voltage (J-V) charact eristics. in which the reverse leakage currents substantially decreased and the Schottky barrier heights increased, when the Sb-and Bi-layer thickness es were appropriate (similar to6 nm for Sb and similar to8 nm for Bi). X-ra y photoelectron spectroscopic (XPS) and secondary ion mass spectroscopic (S IMS) data. together with the J-V characteristics. indicated that the passiv ation effects stem front the probable surface termination of GaAs with Sb m id Bi. the removal of the native oxides of GaAs due to the reductive nature s of Sb and Bi. and suppression of Au diffusion into GaAs by these layers. The GaN/GaAs structure was fabricated by the plasma nitridation of the Sb/G aAs sample in the helicon-wave excited N-2 plasma.