器件级同质外延CVD金刚石膜上的具有高击穿电压的铝肖特基二极管(英文)

High breakdown voltage of Al Schottky diodes on device grade homoepitaxial CVD diamond films

用微波等离子体化学气相沉积方法合成高品质同质外延金刚石膜， 并且用扫描电镜和阴 极荧光分析法评价。为了得到高薄膜生长速率， 把甲烷浓度设定在 4％。薄膜上的生长丘的数 量和大小依赖于生长条件。在本工作的样品中 ,未发现任何非外延晶粒。室温下的阴极荧光分 光结果表明这些金刚石薄膜具有与自由励起子相关的谱峰。氢终端的膜表面制作的铝电极显 示了 P型整流特性 ,击穿电压高于 380V。实验结果表明，阴极荧光分析法观测到的缺陷和电性 能密切相关，并且可以在有室温边发射的金刚石表面上制作具有高击穿电压的整流电极。

High quality homoepitaxial diamond films were synthesized by microwave－ enhanced plasma chemical vapor deposition MPCVD method and were characterized by scanning electronic microscopy (SEM) and cathode luminescence (CL) method. In order to obtain high film growth rate, the methane concentration (CH4/H2) was set at 4％ . Although small pits existed on the films and their numbers depended on the growth condition, no unepitaxial crystals were observed from any sample grown in this study. CL spectra of these diamond films measured at room temperature revealed edge emission. The intensity was larger for sample with small number of pits. Aluminum contacts formed on these hydrogen terminated films showed p－ type rectification properties. The breakdown voltage estimated between Al Schottky contacts and Ti/Au Ohmic contacts with 500μ m in separation was 380V in spite of no elec－ trode grading structure. These results indicate that the gap states confirmed from CL spectra relate strongly to the breakdown voltage of Schottky contacts.