Effect of Microwave Pulse on the Deposition Rate of Hydrogenated Amorphous Silicon in the Electron Cyclotron Resonance Plasma Deposition

Abstract

Hydrogenated amorphous silicon (a-Si:H) films were deposited from Ar and silane gases by a pulsed electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECR PECVD) method. The pulse frequency of the microwave power was varied to study its effect on the deposition rate. It was found that the deposition rate of a-Si:H films is enhanced by about 40% at frequencies which are lower than 25 kHz (where the pulse width is 20 µ s) and abruptly increased up to about 89% and 97% at 27.5 kHz and 30 kHz respectively, compared to the case of the continuous wave. These results suggest that the SiH3 radical be the dominant species responsible for the deposition of a-Si:H. The lifetime of the dominant radicals is estimated as shorter than 20 µ s.