Preparation of a Thin Silicon Nitride Layer by Photo-CVD and Its Application to InP MISFET's

Abstract

Thin silicon nitride (SiN _x ) layers have been successfully prepared by photochemical vapor deposition (photo-CVD) technique. Ellipsometric and X-ray photoelectron spectroscopic studies prove that the refractive index and concentration of nitrogen in the layer are strongly dependent on the substrate temperature. The interface state density at the SiN _x /InP interface is estimated to be 8×10¹¹ cm^-2 eV^-1 from the capacitance-voltage characteristics of InP MIS diodes. Using SiN _x layer as a gate insulator, InP MISFET's were fabricated on semi-insulating InP substrates.