Effect of hydrogen radical exposure on the interfacial and bulk structure of a-Si:H/a-SiNx:H multilayer films

• Published in: Thin solid films 1998-12, Vol.334 (1-2), p.6-10
• Main Authors: Han, Gaorong, Du, Piyi, Shou, Jinhun, Zhao, Danmei
• Format: Article
• Language: English
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Hydrogen radical; Interface; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Multilayer film; Physics; Structure; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(98)01106-7

The a-Si:H/a-SiNx:H multilayer films were prepared by a glow discharge CVD method. Hydrogen radical produced by H2 plasma was alternately exposed to both a-Si:H and a-SiNx:H sublayer surfaces while suspending the deposition of each sublayer. The microstructure of the a-Si:H/a-SiNx:H multilayer films with hydrogen radical exposure and without hydrogen radical exposure was studied by means of small angle XRD, IR and Raman scattering measurements. The results indicate that the induced hydrogen radical may break the distorted or unstable Si–Si bonds on the a-Si:H and a-SiNx:H sublayer surfaces, and that the excessive H atoms at the interfaces of the a-Si:H/a-SiNx:H multilayer films may compensate for the surface silicon dangling bond by forming the Si–H bond. It was found that the microstructure of the multilayer films depends strongly on the hydrogen radical exposure time. The value of the silicon bond angle deviation in the a-Si:H(50A)/a-SiNx:H(50A) multilayer film changes from 10 to 7.9 to 12.1° with increasing hydrogen radical exposure time from 0 to 10 to 60 s, correspondingly. Given the exposure time of 10 s, the multilayer film is of the abruptest interface and smallest deviation of interfacial silicon bond angle.