Highly moisture-resistive silicon nitride films prepared by catalytic chemical vapor deposition and application to gallium arsenide field-effect transistors

Abstract

Moisture resistivity for silicon nitride (SiN x ) films prepared by catalytic chemical vapor deposition (Cat-CVD) was examined. SiN x films prepared by Cat-CVD and those by plasma-enhanced chemical vapor deposition (PECVD) were subjected to the pressure cooker test (PCT) in H 2O vapor at 2 atm and 121°C for 96 h. It was confirmed after PCT that the intensity of the signal due to Si–O bonds in Fourier-transform infrared absorption spectra remarkably increases for PECVD films although little increase is observed for Cat-CVD films. Low stress of the order of 10 MPa was also obtained for SiN x films prepared by Cat-CVD. SiN x passivation by Cat-CVD brings about low leakage current and high mutual conductance for gallium arsenide self-align-gate field-effect transistors.