High‐rate preparation of thin Si films by atmospheric‐pressure plasma enhanced chemical transport

Abstract

Polycrystalline Si films were prepared by chemical transport using near-atmospheric-pressure pure hydrogen plasma (6.7×10 −3 to 5.3 × 10 −2 MPa). Substrate temperatures were varied from 200 to 600• C and solid Si source was used as the feedstock to generate SiH x species. To generate high-density stable glow hydrogen plasma at near atmospheric pressure, 150 MHz very high frequency (VHF) power was used. The dependence of deposition rate on various preparation parameters, such as VHF input power, hydrogen pressure, and substrate temperature, was investigated. The deposition rate increased with increasing VHF power density and substrate temperature. The attained deposition rate on glass substrates was 15 nm/s at 400• C. Prepared Si films exhibited columnar structures along the growth direction. The maximum lateral grain size was 5 µm at the film thickness of 15 µm. It was found by Raman spectroscopy that the crystalline fraction of prepared Si film would not be influenced with increasing deposition rate (R d ).

Purified Silicon Film Formation from Metallurgical-Grade Silicon by Hydrogen-Plasma-Induced Chemical Transport

“…[12][13][14][15][16] In this review article, we describe two new processes to produce purified Si material directly from MG-Si based on the APECT principle. One is the formation of purified Si films using a 150 MHz very high frequency (VHF) H 2 plasma, which is generated in a narrow plasma gap (proximity-type APECT).…”

“…One is the formation of purified Si films using a 150 MHz very high frequency (VHF) H 2 plasma, which is generated in a narrow plasma gap (proximity-type APECT). [12][13][14][15] The other is a new process of SiH 4 gas formation directly from MG-Si using 2.45 GHz microwave H 2 plasma (remote-type APECT). 16,17) Although the experiments were performed in the H 2 pressure range from 100 to 760 Torr, the acronym ''APECT'' is used throughout this article.…”

“…For the efficient fabrication of Si films, we have proposed an atmospheric-pressure plasma-enhanced chemical transport (APECT) method in which no source gas is needed. [12][13][14][15][16] In this review article, we describe two new processes to produce purified Si material directly from MG-Si based on the APECT principle. One is the formation of purified Si films using a 150 MHz very high frequency (VHF) H 2 plasma, which is generated in a narrow plasma gap (proximity-type APECT).…”

Chemical Transport Deposition of Purified Poly-Si Films from Metallurgical-grade Si Using Subatmospheric-pressure H2 Plasma

“…In the previous study [12][13][14], we have reported that a poly-Si film with a wedge-shaped columnar structure was formed at a deposition rate of 15 nm/s. The average grain size in the prepared Si film with the thickness of 4.5 μm was about 2 μm.…”

“…For efficient fabrication of Si films, Ohmi et al [11][12][13][14][15] have proposed atmospheric-pressure plasma enhanced chemical transport (APECT) method in which no source gas is needed. In this method, high-pressure (100 -760 Torr) stable glow plasma of pure H 2 is generated between two parallel electrodes (less than 2 mm apart) by supplying a 150 MHz very high frequency (VHF) power.…”