The role of hydrogen in hydrogenated microcrystalline silicon film and in deposition process with VHF-PECVD technique |
| |
| Authors: | Yang Hui-Dong and Su Zhong-Yi |
| |
| Affiliation: | Department of Electronic Engineering, Jinan University, Guangzhou 510632, China; Department of Electric Engineering, Shanhai Dianji University, Shanghai 200240, China |
| |
| Abstract: | The role of hydrogen in hydrogenated microcrystalline silicon ($\mu $c-Si:H)
thin films in deposition processes with very high frequency
plasma-enhanced chemical vapour deposition (VHF-PECVD) technique have been
investigated in this paper. With \textit{in situ} optical emission spectroscopy (OES)
diagnosis during the fabrication of $\mu $c-Si:H thin films under different
plasma excitation frequency $\nu _{\rm e }$ (60MHz--90MHz), the
characteristic peak intensities ($I_{{\rm SiH}^*}$, $I_{{\rm H}\alpha^*}$
and $I_{{\rm H}\beta ^*}$) in SiH$_{4}$+H$_{2}$ plasma and the ratio
of ($I_{{\rm H}\alpha^* }$ +
$I_{{\rm H}\beta^*}$) to $I_{{\rm SiH}^*}$ were measured; all the characteristic peak
intensities and the ratio ($I_{{\rm H}\alpha^* }$
+ $I_{{\rm H}\beta^* }$)/$I_{{\rm SiH}^*}$ are
increased with plasma excitation frequency. It is identified that high
plasma excitation frequency is favourable to promote the decomposition of
SiH$_{4}$+H$_{2 }$ to produce atomic hydrogen and SiH$_x$ radicals. The
influences of atomic hydrogen on structural properties and that of SiH$_x$
radicals on deposition rate of $\mu $c-Si:H thin films have been studied
through Raman spectra and thickness measurements, respectively. It can
be concluded that both the crystalline volume fraction and deposition rate
are enhanced with the increase of plasma excitation frequency, which is in
good accord with the OES results. By means of FTIR measurements, hydrogen
contents of $\mu $c-Si:H thin films deposited at different plasma
excitation frequency have been evaluated from the integrated intensity of
wagging mode near 640 cm$^{ - 1}$. The hydrogen contents vary from 4{\%} to 5{\%},
which are much lower than those of $\mu $c-Si:H
films deposited with RF-PECVD technique. This implies that $\mu $c-Si:H thin
films deposited with VHF-PECVD technique usually have good stability under
light-soaking. |
| |
| Keywords: | VHF-PECVD technique hydrogenated microcrystalline silicon role of hydrogen optical emission spectroscopy |
| 本文献已被 维普 等数据库收录！ |
| 点击此处可从《中国物理 B》浏览原始摘要信息 |
|
点击此处可从《中国物理 B》下载免费的PDF全文 |
|
