DocumentCode :
1108844
Title :
A Current Estimation Method for Bias-Temperature Stress of a-Si TFT Device
Author :
Shih, Ching-Chieh ; Lee, Yeong-Shyang ; Fang, Kuo-Lung ; Chen, Ching-Hung ; Gan, Feng-Yuan
Author_Institution :
AU Optronics Corp., Hsinchu
Volume :
7
Issue :
2
fYear :
2007
fDate :
6/1/2007 12:00:00 AM
Firstpage :
347
Lastpage :
350
Abstract :
We have studied the time-dependence degradation of ON current of amorphous silicon thin-film transistors (a-Si:H TFTs), which is a function of stress duration, stress temperature, and stress bias. A simple method with stretched-exponential equation and current-voltage function is used to characterize and predict the TFT performance. Bias-temperature stress at different stress voltages has been performed on a-Si:H TFTs. A new method using ON current degradation to analyze TFT device performance is presented, which is different from the conventional threshold-voltage shift method. We have also observed that the beta value in the ON current degradation method compared to the threshold-voltage shift method, with a stretched-exponential stress time, is related to beta~beta0-TST/T0. Finally, we have also used the new equation to evaluate the performance of the gate-driver-on-array circuit in our products. If the limitation of the current for the pull-down device is 1times10-6 A, then the operation time of the pull-down device can be estimated to about 1219 h when key pulled-down TFT is operating at 60degC.
Keywords :
amorphous semiconductors; approximation theory; electric breakdown; silicon; thin film transistors; ON current degradation; Si - Interface; amorphous silicon thin-film transistors; bias-temperature stress; current estimation; current-voltage function; gate-driver-on-array circuit; pulled-down TFT; stress bias; stress duration; stress temperature; stretched-exponential equation; temperature 60 degC; time-dependence degradation; Amorphous silicon; Circuits; Degradation; Electron traps; Equations; Gallium nitride; Stress; Temperature; Thin film transistors; Voltage; Amorphous silicon; BTS; TFT; current estimation; reliability;
fLanguage :
English
Journal_Title :
Device and Materials Reliability, IEEE Transactions on
Publisher :
ieee
ISSN :
1530-4388
Type :
jour
DOI :
10.1109/TDMR.2007.901068
Filename :
4295101
Link To Document :
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