Effect of oxygen contamination on the deposition of hydrogenated amorphous silicon films by tetrode radio frequency sputtering

Hydrogenated amorphous silicon films were deposited using the tetrode rf sputtering method by changing the hydrogen partial pressure ratio ξ to argon in atomospheric gas H2/Ar, under the following conditions: one is the oxygen contaminated condition and the other is the condition which prevents the oxygen contamination with gas filtration and Ar‐plasma cleaning. The effect of oxygen incorporated in the films on the optical and electrical properties of deposited films was studied comparing the properties of the films deposited under both conditions. From the experimental results, we found that (1) in the dependence of the properties of the oxygen contaminated films on ξ, an irreversible phase transition with respect to ξ observed at ξ>10% is a phenomenon which is assisted by oxygen incorporated in the films. (2) The strong infrared absorption at 650 cm−1 observed in the oxygen contaminated films is one of vibration mode of –Si–O–Si–H bonds formed by oxygen incorporated in the films.