Study of NH3 plasma damage on GaAs Schottky diode in inductively coupled plasma system

Si-doped n-GaAs samples were exposed to inductively coupled plasma (ICP) NH 3 discharges at different chuck temperature, pressure, source powers, and r f chuck powers to simulate the effects of ion damage and hydrogen passivati on during SiH4/NH3 silicon nitride deposition for GaAs ICs fabrication. The ideality factor and reverse breakdown voltage of Schottky diodes were used to characterize the plasma damages. Both ideality factor and reverse break down voltage increase with increasing rf chuck power and ICP power because of the reduction of free carriers due to the lattice disorder created by th e ion bombardment. A similar trend was observed with increasing deposition temperature and pressure; however, this is mainly due to the passivation of Si dopants in the GaAs donor layer by hydrogen free radicals and ion bomba rdment damage. The high temperature process enhances the hydrogen diffusion and high pressure produces more hydrogen free radicals and deposition bias voltage increases at both conditions. (C) 1999 The Electrochemical Society . All rights reserved.