Hydrogen distribution in high stability a-Si:H prepared by the hot wire technique

In this work the microstructures of 2-3 hydrogen at.% hot-wire CVD a-Si:H films were characterized by H-1 nuclear magnetic resonance (NMR). Significant differences were found between the hydrogen distribution in these samples and that in conventional plasma-enhanced CVD samples. Among other things, the broad resonance line in the hot-wire a-Si:H is 50 Wt wide, which is much broader than that observed 25-35 kHz in PECVD a-Si:H films. Moreover, a 0.5 kHz resonance absorption hole width due to intrinsic dipolar interactions is obtained using the hole-burning technique. Surprisingly, approximately 90 percent of the hydrogen atoms give rise to the 50 kHz line and only a very small percentage of the hydrogen atoms give rise to the much narrower resonance line.