IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Thin Films Thursday Sessions
       Session TF-ThP

Paper TF-ThP4
Comparison of Poly-Si Films Deposited by UHVCVD and LPCVD and Its Application for Thin Film Transistors

Thursday, November 1, 2001, 5:30 pm, Room 134/135

Session: Thin Film Deposition/Carbon-Containing Films Poster Session
Presenter: D.Z. Peng, National Chiao Tung University, Taiwan
Authors: D.Z. Peng, National Chiao Tung University, Taiwan
H.W. Zan, National Chiao Tung University, Taiwan
T.C. Chang, National Sun Yat-Sen University, Taiwan
C.Y. Chang, National Chiao Tung University, Taiwan
P.S. Shih, National Chiao Tung University, Taiwan
Correspondent: Click to Email
The ultra high vacuum chemical vapor deposition (UHV/CVD) system can deposite poly-Si film without any laser or furnace annealing at lower temperature (550C). The uniformity of threshold voltage and mobility is superior to that deposited by low pressure chemical vapor deposition (LPCVD) system. The threshold voltage and mobility deviation for UHV/CVD are 0.16V, 10%, respectively and 0.23V, 21% for LPCVD system. However, due to the deposition in polycrystalline phase for UHV/CVD, the film surface is rough and results in low field effect mobility (27 cm2/VS, after plasma passivation, p-type device) compared to that (103 cm2/V-s, after plasma passivation, p-type device) obtained by low pressure chemical vapor deposition (LPCVD) using disilane (si2H6) in amorphous phase followed by solid phase crystallization (SPC). It can be shown that poly-Si film thickness will influence the leakage current. In this thesis, NH3, N2 and N2O were used to passivate the devices. They have obvious improvement on device performance after plasma passivation, in addition, NH3 passivation will result in the smallest leakage currrent and highest on/off current ratio. However, N2O needs a longer passivation time compared to the other two. After passivation, the devices show a poor stress endurance compared to unpassivated devices.