Effects of Nitrogen Plasma Treatment on AP-PECVD Fabricated Mg-Doped InGaZnO Channel Thin Film Transistors

• Main Authors: Hung, Jo-Han, 洪若涵
• Other Authors: Chang, Kow-Ming
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/nm56ep

碩士 === 國立交通大學 === 國際半導體產業學院 === 107 === The conventional a-Si thin film transistors (TFTs) have some obviously disadvantages, such as high operation voltage, poor subthreshold swing, threshold voltage and processes temperature issues, and lower field-effect mobility, etc. As the required technology of panels nowadays, such as high resolution, high field-effect mobility and low processes temperature, the conventional thin film transistors are no longer satisfied. However, with high resolution, large size, and high frame rate displays are the trend of 3D display in the future and amorphous indium gallium zinc oxide (a-IGZO) is an appropriate material to fabricate thin film transistors with high mobility and great uniformity, which possess high carrier mobility (>10 cm2/V·s), high transparency and low processes temperature compared to amorphous silicon thin film transistors (a-Si TFTs). Furthermore, the process steps of a-IGZO TFTs are more simple than low temperature poly crystalline silicon thin film transistors (LTPS TFTs) with low cost and the uniformity of a-IGZO TFTs are better than LTPS TFTs. In this research, a-Mg-IGZO double channel layer is fabricated by atmospheric-pressure PECVD (AP-PECVD) in atmosphere, with nitrogen plasma treatment to optimize the interface between insulating layer and IGZO-active layer. The AP-PECVD is without vacuum system so that we could not only save a lot of cost to maintain it also apply to large area manufacturing, and the nitrogen plasma treatment is also treated by AP-PECVD, rapid and consistent process flow can also reduce the divergence of a-IGZO TFT with good reliability and reduce the process time, to achieve low temperature process. Finally, we successfully fabricated a-Mg-IGZO TFT by AP-PECVD to deposit IGZO double channel and optimize the interface between insulating layer and active layer with nitrogen plasma treatment. It reveals that the performance of thin film transistor has significant improvement for the case with 600W of nitrogen plasma treatment for 60s and it exhibited highest mobility of 18.9 cm2/V·s and smallest subthreshold swing of 91.3 mV/decade, compared to without nitrogen plasma treatment case exhibited mobility of 12.0 cm2/V·s and subthreshold swing of 151.9 mV/decade. Obviously, amorphous InGaZnO TFT devices have significantly improvement by nitrogen plasma treatment.