Aluminum Gallium Nitride Heterostructures for High Temperature Transistor and Sensor Applications

该计划旨在开发用于高温传感器和电子应用的氮化铝镓异质结构器件。我们将专注于高电子迁移率晶体管（或HEMT）用于高温微波器件或作为一个敏感的紫外线探测器。氮化镓具有3.2 eV的大带隙，这使得它比砷化镓具有更高的击穿电压和更高的饱和电子速度。此外，它在空气中稳定到800℃左右，这使其成为高温HEMT器件使用的理想选择。HEMT器件在功率放大和低噪声放大方面都非常出色，因为它们具有高载流子浓度和增强的载流子迁移率。它们的功率和噪声性能随着异质结构界面势垒的增加而增加。提出了采用独特的原子层外延方法制备高n掺杂高光学质量薄膜的第一阶段计划。目前所有的生长和掺杂方法都不能产生低电阻率的涂层。第一阶段计划的成功，结合我们在铝浓度低于20%的异质结中展示的高质量薄膜和增强的电子迁移率，将为第二阶段HEMT制造工作奠定坚实的基础。

The proposed program is aimed at developing aluminum gallium nitride heterostructure devices for high temperature sensor and electronics applications. We will focus on the high electron mobility transistor (or HEMT) for use as a high temperature microwave device or as a sensitive ultraviolet detector. Gallium nitride has a large bandgap of 3.2 eV which gives it a greater breakdown voltage and a higher saturated electron velocity than gallium arsenide. In addition, it is stable in air to around 800oC which makes it ideal for high temperature HEMT device use. HEMT devices are excellent for both power and low noise amplification since they posses a high carrier concentration and enhanced carrier mobility. Their power and noise performance increases with the potential barrier at the heterostructure interface. A Phase I program is proposed to produce high n-doped good optical quality films using a unique atomic layer epitaxy approach. All the present day growth and doping procedures cannot produce low resistivity epilayers. A successful Phase I program combined with our demonstration of high quality films and enhanced electron mobilities in heterojunctions with aluminum concentrations less than 20% will form a strong basis for a Phase II HEMT fabrication effort.