Bending Effect of Si MOSFETs on Flexible Plastic Substrate

• Main Authors: Po Shou Lin, 林柏壽
• Other Authors: H. L. Kao
• Format: Others
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/75659639632386716785

碩士 === 長庚大學 === 電子工程學研究所 === 97 === Flexible electronics have got a lot of attention for portable electronics product due to their properties of lightness and easy to minimize. However, the performance of flexible electronic device is limited by the low-temperature amorphous, polycrystalline Si thin-film transistors (TFTs). They have relatively lower mobility compared with single crystal Si MOSFETs and can not achieve the high performance on the flexible plastic. For this reason, the single crystal Si MOSFET seems a good candidate in terms of their higher speed and mature technology. There is a challenge for integrating Si MOSFET into plastic substrate, because transistors are needed to be thinned down to 100 μm first and then mounted on plastic with little performance degradation. After that, due to the high flexibility of the thin body thickness (tsub) and plastic substrate, a large external mechanical stress (proportional to 1/tsub2) would be applied for more device performance improvement. This technique is based on the strained-silicon technology except that strain is made from externals, not inside, which is created during the fabrication. The bending effect may cause something changed or even better, such as drain current, mobility or threshold voltage. That is why we use this way in our research to improve the performance of electronic device on flexible substrate. In the beginning, we will introduce the current application of flexible electronics. In the second part, the theory is going to talk about how strain effect can make energy band split and mobility up. Next is the third part, the experimental procedure will be briefly presented like apparatus installation and simulation software, TMA and Ansys10.0, with background concept and operation instructions, respectively. The fourth part will check and analyze some important characteristics from steps, including before and after thinning, before and after bending and the other issues or problems happened in our experiment. We will summarize all our viewpoints and conclusion, based on measured and simulated data in the final part.