Investigation of strain-engineering techniques for modification of the characteristics of FETs in polar III-nitride material system and analytical modeling of device peculiarities

在过去的十年中，极性AlGaN/GaN异质结场效应晶体管(HFET)一直是器件研究界关注的焦点，成为高功率、高压微波应用的诱人候选者。宽禁带AlxGa1-xN材料系统的高温稳定性和较高的击穿电压，促进了AlGaN/GaN HFET在高电压/高温条件下作为开关应用的重要候选材料的适用性。随着对提高传感设备可靠性的需求日益增长，以及电动汽车的普及，能够在硅技术所提供的温度和电压范围之外工作的节能型固态电子电路的需求越来越大。就PI所知，还没有从提供常断(零栅电压下的零电流)重载的工艺开发要求和可重复制造常断/常通(零栅电压下的非零电流)对的挑战的角度，对宽带隙极性III-氮化物材料系统在开关模式电子设备中的应用进行系统的研究。这项发现拨款提案的结果将改进极性材料系统中固态电子设备和电路的分析、设计和评估方法，以便有效地利用这一相对较新的电子材料家族的材料特性。此外，还将建立包含AlGaN/GaN HFET漏电流崩塌和过度栅漏的分析模型。

During the past decade, polar AlGaN/GaN heterostructure field effect transistors (HFETs) have been the focus of the device research community as alluring candidates for high power, high voltage microwave applications. High temperature stability and large breakdown voltage of wide-bandgap AlxGa1-xN material system, promote the applicability of AlGaN/GaN HFETs as vital candidates for switching applications under high-voltage/high-temperature conditions. In light of the growing demand for reliability improvement of the sensory equipment and surge in popularity of electric vehicles, power-prudent solid state electronic circuits capable of operating at temperature and voltage ranges beyond those offered by silicon technology are in demand. To the best of the PI's knowledge, a systematic investigation of the application of wide-bandgap polar III-Nitride material system to switching-mode electronics from the standpoints of process-development requirements for offering normally-off (zero current at zero gate voltage) HEFTs and challenges of reproducible fabrication of normally-off/normally-on (nonzero current at zero gate voltage) pair has not been performed. Results of this Discovery Grant proposal will lead to improved methods for analysis, design, and evaluation of solid state electronic devices and circuits in polar material systems for the efficient exploitation of the material properties of this relatively new family of electronic materials. Moreover, analytical models will be developed for incorporation of drain-current collapse and excessive gate leakage of AlGaN/GaN HFETs.