The Dependence of ECR-CVD Processing Parameters on Deposition Uniformity of Hydrogenated Amorphous Silicon (a-Si:H) Films

2015 ◽  
Vol 656-657 ◽  
pp. 92-100
Author(s):  
Li Cheng Hu ◽  
Yong Shiang Li ◽  
Chien Chieh Lee ◽  
Jeng Yang Cheng ◽  
I Chen Chen ◽  
...  

The uniformity improvement of high deposition rate in hydrogenated amorphous silicon (a-Si:H) film deposited by electron cyclotron resonance chemical vapor deposition (ECR-CVD) is very essential for a large substrate in PV solar industry. In order to improve the uniformity in depositing thin film in large area, the auxiliary magnetic coils were designed and installed in ECR-CVD to modify the distribution of magnetic field. In addition, the dependence of the other ECR-CVD processing parameters such as resonance position, microwave power, working pressure, and substrate temperature were investigated. The results indicated that more uniform a-Si:H film could be obtained when working pressure was decreased. By using finite element analysis, it was found that location of turbo pump would impact gas flow field and this effect would become more significant at high pressure. Increasing microwave power, increasing horizontal gradient of the magnetic field to the substrate, and forming Cusp magnetic field could enhance ECR-CVD deposition uniformity greatly. However, the plasma location and substrate temperature were not major factors affecting a-Si:H film uniformity in ECR-CVD process. Finally, the optimal and the best 3.8% in uniformity could be achieved in 150mm diameter when the ratio of magnetic field strength at wafer edge to wafer center is 215%, working pressure is 1.5 mtorr, microwave power density is 4W/cm2, and substrate temperature is 180°C.

2003 ◽  
Vol 762 ◽  
Author(s):  
Guofu Hou ◽  
Xinhua Geng ◽  
Xiaodan Zhang ◽  
Ying Zhao ◽  
Junming Xue ◽  
...  

AbstractHigh rate deposition of high quality and stable hydrogenated amorphous silicon (a-Si:H) films were performed near the threshold of amorphous to microcrystalline phase transition using a very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) method. The effect of hydrogen dilution on optic-electronic and structural properties of these films was investigated by Fourier-transform infrared (FTIR) spectroscopy, Raman scattering and constant photocurrent method (CPM). Experiment showed that although the phase transition was much influenced by hydrogen dilution, it also strongly depended on substrate temperature, working pressure and plasma power. With optimized condition high quality and high stable a-Si:H films, which exhibit σph/σd of 4.4×106 and deposition rate of 28.8Å/s, have been obtained.


1995 ◽  
Vol 78 (1) ◽  
pp. 317-320 ◽  
Author(s):  
J. P. Kleider ◽  
C. Longeaud ◽  
M. Barranco‐Diaz ◽  
P. Morin ◽  
P. Roca i Cabarrocas

1996 ◽  
Vol 420 ◽  
Author(s):  
W. Futako ◽  
I. Shimizu ◽  
C. M. Fortmann

AbstractHydrogenated amorphous silicon (a-Si:H) with a gaps narrower than 1.7 eV were made by repeating the deposition of a thin layer (1–3 nm thick) and the treatment of growing surface with a mixture of H and Ar*. Crystallization induced by permeation of hydrogen into the subsurface at high substrate temperature (>200C) was efficiently prevented by treating with a mixture of H and Ar*. The activation of growing surface may arise from releasing a part of hydrogen on surface by treating with Ar*. High quality a-Si:H films containing hydrogen of 3 atom % with a gap of 1.6 eV were made by chemical annealing with a mixture of H and Ar*.


1984 ◽  
Vol 23 (Part 2, No. 2) ◽  
pp. L81-L82 ◽  
Author(s):  
Toshihiko Hamasaki ◽  
Masato Ueda ◽  
Akiyoshi Chayahara ◽  
Masataka Hirose ◽  
Yukio Osaka

1992 ◽  
Vol 283 ◽  
Author(s):  
R. Carluccio ◽  
A. Pecora ◽  
G. Fortunato ◽  
J. Stoemenos ◽  
N. Economou

ABSTRACTExcimer laser crystallization of hydrogenated amorphous silicon has been investigated as a function of substrate temperature. At low substrate temperatures hydrogen out-diffusion strongly influences the film morphology, while at 420 °C homogeneous recrystallized films are obtained, as a result of the reduced solidification velocity. This process has been successfully tested by fabricating with the recrystalllized material thin-film transistors according to the bottom-gate configuration.


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