Capturing H and H2 by SiHx+ (x ≤ 4) ions: Comparison between Langevin and quantum statistical models. (10th January 2017)

• Record Type: Journal Article
• Authors: Nguyen, Trong-Nghia; Lee, Yun-Min; Wu, Jong-Shinn; Lin, Ming-Chang
• Is Part Of: Japanese journal of applied physics. Volume 56:Number 2(2017)
• Publication Date: 2017-01-10
• Subjects: Physics -- Periodicals; 621.05
• DOI: 10.7567/JJAP.56.026101
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: H, H2, and SiH x + ( x ≤ 4) ions coexist under plasma-enhanced chemical vapor deposition (PECVD) conditions. We have studied the kinetics of their interactions by high-level quantum chemical and statistical theory calculations, and compared the results with classical Langevin values (∼2 × 10 −9 cm 3 molecule −1 s −1 independent of temperature). The results indicate that, for H capturing by SiH x + ( x ≤ 4), both theories agree within a factor of 2–4, whereas for H2 capturing by SiH x + ( x ≤ 3), the modern theory gives higher and weakly temperature-dependent values by up to more than one order of magnitude, attributable to reaction path degeneracies and increased entropies of activation. The heats of formation and structural parameters of SiH x + ions ( x ≤ 5) in this work agree well with available experimental data. For practical applications, we have provided tables of rate constants for modeling various processes of relevance to the PECVD of a-Si:H films.