Investigation of electron divices for hard atmosphere using heteroepitaxial diamond layr

1)同轴波导大面积微波等离子体化学气相沉积技术的发展：利用同轴波导研制了新型微波等离子体化学气相沉积技术。取得了以下结果。a）等离子体的包围，B）金刚石成核所需的离子能量（20-30 eV）的可控性，以及c）在200 Torr以上的等离子体的稳定性，其中预期结晶度的改善。2）异质外延金刚石的初始生长阶段的观察：使用高分辨率SEM研究了金刚石成核所需的SiC的表面结构。基于观察，高密度的成核导致顺利的异质外延生长已被实现作为结果。3）MESFET的异质外延金刚石层上的制造：金属半导体场效应晶体管（MESFET）具有5 μ m的栅极长度已被制造的异质外延金刚石层上。器件的性能与同质外延金刚石表面的器件相当。获得的金刚石异质外延层的最大介电常数（gm）为7- 8 mS/mm。4）NAND、NOR、R-S触发器电路和MOSFET：在同质外延层上，NAND、NOR、R-S触发器电路已经运行。已研制出gm为15 mS/mm、工作温度高达350 ℃、与Si n-MOSFET相当的MOSFET，这是目前金刚石FET中最先进的一项成果

1) Development of large area microwave plasma CVD using coaxial waveguide :Using coaxial waveguide new type of microwave plasma CVD has been developed. The following results have been obtained. a) Enlargement of plasma, b) controllability of ion energy (20-30 eV) necessary for diamond nucleation, and c) stability of plasma above 200 Torr where the improvement of crystallinity has been expected.2) Observation of initial growth stage of heteroepitaxial diamond :Using high resolution SEM the surface structure of SiC necessary for diamond nucleation has been investigated. Based on the observation the high density of nucleation leading to smooth heteroepitaxial growth has been realized as a result.3) MESFET fabrication on the heteroepitaxial diamond layrs :Metal semiconductor field effect transistors (MESFETs) with 5mum gate length have been fabricated on the heteroepitaxial diamond layrs. The performance of the devices are comparable to those on homoepitaxial diamond surfaces. The obtained transconductance (gm) are 7-8mS/mm, which is the highest in diamond heteroepitaxial layr. It reflect the high hole mobility of the heteroepitaxial layr.4) NAND,NOR,R-S flip-flop circuits and MOSFET :On homoepitaxial layr, NAND,NOR,and R-S flip-flop circuits have been operated. The MOSFETs with the gm of 15mS/mm comparable to Si n-MOSFET have been developed and operated up to 350ﾟC.This result is the most advanced one in diamond FETs