Infrared absorption and hydrogen effusion of hydrogenated amorphous silicon-oxide films

Abstract IR absorption, hydrogen effusion as well as hydrogen–deuterium interdiffusion were studied on plasma-grown boron doped and undoped hydrogenated silicon-oxide (a-Si:O:H) films. A structural transition from a compact material to a material with an interconnected void structure is observed at an oxygen concentration near 20 at.% and attributed to hydrogen-induced void formation. Differences between a-Si:O:H films and hydrogenated amorphous silicon–carbon (a-Si:C:H) films are observed: For compact material, the H diffusion coefficient decreases with increasing alloy component for a-Si:C:H while it increases for a-Si:O:H. Effusion measurements of implanted inert gases indicate a void structure with larger pores in a-Si:C:H than in a-Si:O:H.