The use of PECVD SiNx layers on p-GaN is complicated by the fact that atomic hydrogen exposure decreases the hole concentration in the GaN through formation of neutral Mg-H complexes and can also lead to preferential loss of nitrogen from the near-surface region which further decreases the p-GaN conductivity. We have exposed p-GaN rectifiers to SiH4/NH3 rf-plasmas during PECVD of thin SiNx passivation layers and measured the effect on both reverse breakdown voltage and diode ideality factor. (C) 2002 Published by Elsevier Science Ltd.