Variation of microstructure and transport properties with filament temperature of HWCVD prepared silicon thin films

• Published in: Thin solid films 2011-05, Vol.519 (14), p.4506-4510
• Main Authors: Gogoi, Purabi, Jha, Himanshu S., Agarwal, Pratima
• Format: Article
• Language: English
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Density; Deposition; Exact sciences and technology; Filaments; Grain boundaries; HWCVD; Hydrogen storage; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Microstructure; Nanocrystalline silicon; Nanocrystals; Nanoscale materials and structures: fabrication and characterization; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Other topics in nanoscale materials and structures; Physics; Silicon films; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Thin films
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2011.01.316

Thin films of hydrogenated silicon are prepared by varying the filament temperature (T F) (1600–1900 °C) at a deposition rate of 8–12 Å/s without using any hydrogen dilution. While the films deposited at low T F are amorphous in nature, those deposited at higher T F (≥ 1800 °C) contain nanocrystallites embedded in the amorphous network. The optical band gap (E 04) of the films (~ 1.89–1.99 eV) is slightly higher compared to the regular films, which is attributed to the improved short and medium range order as well as the presence of low density amorphous tissues in the grain boundary regions. The films show improved stability under long term light exposure due to more ordered structure and presence of hydrogen mostly as strong Si–H bonds.