Verification of Stability of CaF2/diamond MIS Interface and Application to HT-MISFET

金刚石薄膜技术在不断发展的今天，通过硼掺杂技术可获得p型半导体金刚石薄膜。现在是将金刚石扩展到实际电子应用的时候了。目前，本课题组对金刚石表面和界面的评价与控制进行了研究。在本项目中，我们重点研究了氟化和氧还原对金刚石表面稳定非常有效的作用。主要结果如下：(1)氧吸附不利地引入了固定表面带的表面态。(2)在金刚石表面沉积CaF2时，Ca原子起到吸氧剂的作用。(3)氟原子直接与表面碳原子结合，稳定了表面电学性能。(4)我们通过CaF2/金刚石MIS结构得到了很好的界面，因此制作的MISFET工作得很好。首次获得了性能正常的金刚石MISFET。

Dimond thin film technology is growing up today, and p-type semiconductive diamond film has been obtainable reproducively by boron doping technique. It is the time to extend diamond to the actual electronic applications.So far, our group conducted research on evaluation and control of diamond surface and interface. In this project, we have focused role of fluorination and oxygen reduction very effective for diamond surface stabilization.Major results are as follows :(1) Oxygen adsorption unfavorably introduces the surface states which pin the surface band.(2) Ca atom serves as oxygen-getter during CaF2 deposition on diamond surface.(3) Fluorine atom directly bonds with surface carbon atom and stabilizes the surface electrical property.(4) We have got pretty nice interface by CaF2/diamond MIS structure, and MISFET made thus worked quite well. We obtained for the first time diamond MISFET with normally off property.