Poly-SiGe TFTs Fabricated by Low Temperature Chemical Vapor Deposition at 450°C

2001 ◽  
Vol 686 ◽  
Author(s):  
Kousaku Shimizu ◽  
Jianjun Zhang ◽  
Jeong-woo Lee ◽  
Jun-ichi Hanna

AbstractLow temperature growth of poly-SiGe has been investigated by reactive thermal chemical vapor deposition technique, which is a newly developed technique for preparing polycrystalline materials with using redox reactions in a set of source materials, Si2H6 and GeF4.. In order to prepare high uniformity and reproducibility of Si-rich poly-SiGe, total pressure, gas flow ratio, and residence time are optimized at 450°C of substrate temperature. Through optimizing the conditions, poly-Si1−xGex (x<0.04) films have been prepared in the reproducibility more than 90% and uniformity more than 88%. Bottom gate type of n-channel thin film transistors has been fabricated in various grain size of poly-Si1−xGex on SiO2 (100nm)/Si substrates. 5-36 cm2/Vs of field effect mobility of thin film transistors (L/W = 50μm/50μm) have been achieved after hydrogenation, whose threshold voltage is around 2±0.5V, and on/off ratio is more than 104.

MRS Advances ◽  
2016 ◽  
Vol 2 (29) ◽  
pp. 1533-1538 ◽  
Author(s):  
S. Ishihara ◽  
Y. Hibino ◽  
N. Sawamoto ◽  
T. Ohashi ◽  
K. Matsuura ◽  
...  

ABSTRACTMolybdenum disulfide (MoS2) thin films were fabricated by two-step chemical vapor deposition (CVD) using (t-C4H9)2S2 and the effects of temperature, gas flow rate, and atmosphere on the formation were investigated in order to achieve high-speed low-temperature MoS2 film formation. From the results of X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) investigations, it was confirmed that c-axis orientation of the pre-deposited Mo film has a significant involvement in the crystal orientation after the reaction low temperature sulfurization annealing and we successfully obtained 3 nm c-axis oriented MoS2 thin film. From the S/Mo ratios in the films, it was revealed that the sulfurization reaction proceeds faster with increase in the sulfurization temperature and the gas flow rate. Moreover, the sulfurization under the H2 atmosphere promotes decomposition reaction of (t-C4H9)2S2, which were confirmed by XPS and density functional theory (DFT) simulation.


1998 ◽  
Vol 508 ◽  
Author(s):  
A. Izumi ◽  
T. Ichise ◽  
H. Matsumura

AbstractSilicon nitride films prepared by low temperatures are widely applicable as gate insulator films of thin film transistors of liquid crystal displays. In this work, silicon nitride films are formed around 300 °C by deposition and direct nitridation methods in a catalytic chemical vapor deposition system. The properties of the silicon nitride films are investigated. It is found that, 1) the breakdown electric field is over 9MV/cm, 2) the surface state density is about 1011cm−2eV−1 are observed in the deposition films. These result shows the usefulness of the catalytic chemical vapor deposition silicon nitride films as gate insulator material for thin film transistors.


2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744101 ◽  
Author(s):  
Bitao Chen ◽  
Yingke Zhang ◽  
Qiuping Ouyang ◽  
Fei Chen ◽  
Xinghua Zhan ◽  
...  

SiNx thin film has been widely used in crystalline silicon solar cell production because of the good anti-reflection and passivation effect. We can effectively optimize the cells performance by plasma-enhanced chemical vapor deposition (PECVD) method to change deposition conditions such as temperature, gas flow ratio, etc. In this paper, we deposit a new layer of SiNx thin film on the basis of double-layers process. By changing the process parameters, the compactness of thin films is improved effectively. The NH3passivation technology is augmented in a creative way, which improves the minority carrier lifetime. In sight of this, a significant increase is generated in the photoelectric performance of crystalline silicon solar cell.


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