由于InN材料具有各向异性的特性, 其电子迁移率沿c轴(Γ-A方向)和底面(Γ-M方向)不同, 同时, 其负微分电阻率在不同晶向上也不同。利用Farahmand Modified Caughey Thomas(FMCT)迁移率模型描述了InN材料在不同晶向上的电子输运特性, 利用文中提出的参数提取方法分别提取了InN在不同晶向上的FMCT模型参数。为了将InN材料的各向异性特性应用于耿氏(Gunn)二极管的制作, 使用Silvaco-atlas半导体仿真软件对纤锌矿InN n+nn+和n+n-nn+两种结构的耿氏二极管进行数值仿真, 对沿两个晶向上制作的InN耿氏二极管的输出特性进行了比较。结果表明: InN耿氏二极管沿Γ-A方向比沿Γ-M方向获得的频率和转化效率更高。InN材料沿Γ-A方向更适合制作耿氏二极管, 该研究为制作InN耿氏二极管提供了参考。

The anisotropic property of InN material leads to different electron mobility in the c-axis (Γ-A direction) and along the basal plane (Γ-M direction) and the negative differential resistivity is also different in different crystal orientations. In this paper, the farahmand modified caughey thomas mobility (FMCT) model was used to describe the electron mobility in different crystal orientations and the model parameters were extracted. In order to apply the anisotropy characteristic of InN in the fabrication of Gunn diodes, numerical simulations were performed on the characteristics of wurtzite InN Gunn diodes with the two structures of n+nn+ and n+n-nn+ with Silvaco-atlas platform. The output characteristics of the diodes along the two different crystal orientations were compared, and the results show that InN Gunn diodes along Γ-A direction obtains higher fundamental frequency and conversion efficiency than that along Γ-M direction. Thus, InN along Γ-A direction is more suitable for fabricating Gunn diode.