The study on vertical-channel oxide-based thin film transistors

• Main Authors: Lai, Hsuan-Ying, 賴宣穎
• Other Authors: Liu, Potsun
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/yp5k2c

碩士 === 國立交通大學 === 顯示科技研究所 === 101 === We had successfully realized vertical-channel amorphous IGZO thin film transistors with submicron channel length (500nm). The device performance of the fabricated V-TFT was evaluated with the characteristics of Ion/Ioff current ratio greater than 106. The source and drain were separated by a insulator for V-TFTs, it meaned that the thickness of this insulator decided the channel length. The structure analysis of scanning electron microscopy was implemented to confirm the vertical structure of the TFT. We study the asymmetric structure and the electrode contact properties by switching the source and drain as we measuring the device performance. Besides, we find that the defects appeared in the a-IGZO channel region in deposition process of the PECVD SiO2 gate dielectric. This is the reason for non-optimum device performance and reliability.　Finally, the reliability analysis for the V-TFTs was applied such as gate bias stress and light illumination sensitivity. The PGBS reliability analysis for our devices exhibits some negative threshold voltage shifts as the stress time increase, and the NGBS reliability analysis for that exhibits positive threshold voltage shifts to 4.1V as the stress time increase to 120 min. In terms of photo-reliability, the device is not sensitive to the environmental light, so it has nice resistance to light.