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在硅衬底晶格匹配In_(0.17)Al_(0.83)N/GaN异质结外延片上制备了Ti/Al/Ni/Au欧姆接触传输线模型测试结构,通过测试变温电流-电压特性研究方块电阻(R_(sh))和比接触电阻率(ρ_(sc))的温度依赖特性.结果表明:(1)沟道层的R_(sh)对温度呈指数依赖关系,幂指数约-2.61,主要由高温下半导体的晶格散射机制决定;(2)300~523 K的变温范围内,ρ_(sc)随温度上升呈先增大后减小的趋势;当温度低于350 K时,ρ_(sc)的温度依赖关系主要由TiN合金的类金属特性决定;而在更高的温度下,热场发射机制将逐渐占主导.基于以上2种模型的并联形式对实验数据进行了拟合,并分析了提取的重要物理参数.
A Ti / Al / Ni / Au ohmic contact transmission line model test structure was fabricated on a lattice-matched In_ (0.17) Al 0.83 N / GaN heterojunction epitaxial wafer of silicon substrate by testing the current- (Sh) and specific resistivity (ρ sc), the results show that: (1) The R_ (sh) of the channel layer is exponentially dependent on the temperature and the power index is about -2.61, (2) ρ_ (sc) increases first and then decreases with increasing temperature in the temperature range of 300 ~ 523 K. When the temperature is lower than 350 K, ρ_ (sc ) Is mainly determined by the metal-like properties of TiN alloys, while at higher temperature, the thermal field emission mechanism will gradually dominate.The experimental data are fitted and analyzed based on the parallel connection of the above two models Extracted important physical parameters.