The interface state density between amorphous hydrogenated material and an insulating film of amorphous H-doped SiN1.7 or SiO2 was measured by using photothermal deflection spectroscopy and electron spin resonance methods. The interface state density in SiN/Si structures was lower than that in amorphous hydrogenated material, while that in SiO2/Si structures was higher than that in amorphous hydrogenated material. The difference in the surface state densities of these specimens was considered in terms of plasma surface reactions. The effect of plasma reaction was examined by treating the surface of the amorphous hydrogenated layers. The results indicated that interface defects in SiO2/Si structures were introduced by plasma reaction with the surface of the amorphous hydrogenated material during the initial stages of deposition. Differences in the interface defect density were attributed to differences in the precursor which was used to deposit the upper layer. Surface chemical reaction of the amorphous hydrogenated material with a source gas introduced interface defects in the initial stages of deposition of the insulating layer.

Effect of plasma treatment on the density of defects at an amorphous Si:H-insulator interface I.Umezu, T.Kuwamura, K.Kitamura, T.Tsuchida, K.Maeda: Journal of Applied Physics, 1998, 84[3], 1371-7