Growth of microcrystalline silicon film by electron beam excited plasma chemical vapor deposition without hydrogen dilution

Abstract

Unique characteristics have been obtained for silicon films grown by electron beam excited plasma chemical vapor deposition (EBEP-CVD) in comparison with films grown by conventional plasma CVD. The EBEP-CVD growth of silicon films on single-crystal Si and SiO2 substrates was investigated using SiH4 without hydrogen dilution as a function of SiH4 flow rate, discharge current, chamber pressure, substrate temperature, and electron acceleration voltage. Typical growth rate was ∼0.1 nm/s. Characterization by Raman scattering spectroscopy showed that all the films were microcrystalline with a grain size of approximately 10 nm; the peak intensity ratio of the crystalline portion was greater than 0.6. The hydrogen concentration in the silicon layer under “standard” growth condition was determined by elastic recoil detection analysis to be as much as 19 at. %. This high level of hydrogen incorporation, considered to be facilitated by EBEP of SiH4 gas, seems to play a critical role in the growth process.