Investigation of Hydrogen and Nitrogen Thermal Stability in PECVD a-Sinx:H.

Abstract

ABSTRACTWe study the high temperature (≤1300°C) thermal evolution from hydrogenated amorphous silicon nitride (a-SiNx:H) films prepared by plasma enhanced chemical vapor deposition. Two principle peaks are found, one at 525–750°C associated with hydrogen release, and one at ≥950°C from hydrogen and nitrogen release. In nitrogen-rich films (x>4/3), the low temperature (525°C) peak intensity is smaller compared to silicon-rich films (x≤4/3), implying that hydrogen is more thermally stable in N-rich films. Helium dilution during film growth further reduces the low temperature peak intensity, producing the most thermally stable N-rich material, with the onset of hydrogen evolution occurring at ∼600°C. For a nitrogen-rich film, high temperature hydrogen evolution began at ∼900°C and was accompanied by nitrogen evolution starting at ∼950°C. UV-illumination of N-rich samples prior to thermal evolution produced no observable changes in the evolution spectra.