Remote PECVD silicon nitride films with improved electrical properties for GaAs P-HEMT passivation

In order to obtain thin silicon nitride films with excellent electrical and mechanical properties, we employed RPECVD (Remote Plasma Enhanced Chemical Vapor Deposition) process which produces less plasma-induced damage than the conventional PECVD. Through the optical and electrical measurements of the deposited films, we optimized the various RPECVD process parameters. The optimized silicon nitride films showed excellent characteristics such as small etch rate (∼33 Å/min by 7:1 BHF), high breakdown field (>9 MV/cm), and low compressive stress (∼3.3×10 ⁹ dyne/cm ²). We successfully applied thin RPECVD silicon nitride films to the surface passivation of GaAs pseudomorphic high electron mobility transistors (P-HEMTs) with negligible degradations in DC and RF characteristics.