Uniform, High Performance Poly-Si TFTs Fabricated by Laser- Crystallization of PECVD-Grown a-SI:H

2000 ◽  
Vol 621 ◽  
Author(s):  
D. Toet ◽  
T.W. Sigmon ◽  
T. Takehara ◽  
C.C. Tsai ◽  
W.R. Harshbarger
Keyword(s):  
Vapor Deposition ◽  
Polycrystalline Silicon ◽  
High Performance ◽  
Chemical Vapor ◽  
Laser Crystallization ◽  
Silicon Thin Film ◽  
Partial Melt ◽  
Amorphous Si ◽  
Average Size ◽  
Si Films

ABSTRACTPolycrystalline silicon thin film transistors (TFTs) were fabricated using laser crystallization of thin amorphous Si films grown by plasma-enhanced chemical vapor deposition. The films were exposed to a scanned XeCl excimer laser beam at 350 mJ/cm2. At this fluence the Si film com- pletely melted and crystallized in the form of uniformly distributed grains with an average size of 39 nm. One of the films was then subjected to a low fluence laser scan (250 mJ/cm2), which re- sulted in the melting of the top part of the film and lead to an increase in grain size. The TFTs fabricated without the partial melt method had good electrical properties and uniformities. The partial melt method lead to substantial improvements in most device characteristics, while the uniformity remained good.

Structure of Polycrystalline Silicon Films by Glow-Discharge Decomposition using SiH4/H2/SiF4 at Low Temperature

1999 ◽  
Vol 581 ◽  
Author(s):  
R. Tsuchida ◽  
M. Syed ◽  
T. Inokuma ◽  
Y. Kurata ◽  
S. Hasegawa
Keyword(s):  
Power Supply ◽  
Vapor Deposition ◽  
Local Structure ◽  
Polycrystalline Silicon ◽  
Chemical Vapor ◽  
High Angle Boundary ◽  
Rf Power ◽  
Nanocrystalline Structures ◽  
Si Films ◽  
Polycrystalline Silicon Films

ABSTRACTFor poly-Si films prepared by a plasma-enhanced chemical vapor deposition, we examined the changes in the local structure caused by adding H2 and/or SiF4 in the SiH4 feed gases and by changing supplied rf power values. The conditions of low rf power supply, low H2 addition, and SiF4 addition allow formation of films with microcrystalline or nanocrystalline structures. In addition, the H2 or SiF4 addition was found to be effective in promotive growth of <111> or <110> grains, respectively. In such low crystallized films, it was suggested that high-angle boundary would be formed, leading to a decrease in the density of SiH2 and Si dangling bonds, and to an increase in g values.

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