高增益碳化硅紫外光电晶体管基础问题研究

The ultraviolet detectors have many applications in military and civil affairs. Due to the wide bandgap, SiC is an excellent material for ultraviolet detectors. For practical applications where very low signals of light are detected, using a detector with inherent gain is necessary. There are many reports on the SiC avalanche photodiodes. But up to now there are few reports on the fabrication of SiC phototransistor with high gain. This project will carry out the research on the basic problems of SiC ultraviolet phototransistors with high gain. By means of the analytic calculation, simulation and process experiments, the physical models of the SiC MESFET and BJT phototransistors will be constructed. The influence mechanism of the parameters of device structure, SiC material properties and the fabrication process parameters on the properties of the SiC MESFET and BJT phototransistor, such as responsivity, optical gain, response speed, detectivity and rejection ratio, will be revealed in this research. Based on the above study, the optimization schemes and prototypes of SiC MESFET and BJT UV phototransistors will be obtained. The achievements of this research will provide some guidances for the design and fabrication of the SiC UV phototransistor in the further research and application.

紫外探测技术在军事和民用方面具有重要的应用价值，宽禁带半导体SiC材料是制备紫外探测器的优秀材料之一。鉴于无增益的SiC紫外光电二极管无法满足对微弱紫外光信号探测的应用需求，研制具有增益的SiC紫外探测器具有重要意义。目前，国内外在这方面的研究主要集中在SiC雪崩光电二极管的研制上，对同样具有增益的SiC紫外光电晶体管的深入研究却还没有。因此，本项目提出开展SiC紫外光电晶体管的基础问题研究，通过理论计算、模拟仿真、工艺实验等手段，揭示4H-SiC 材料基于MESFET、BJT 结构的紫外光电晶体管的工作机理；建立器件结构参数、SiC材料参数和工艺参数与器件的光增益、响应率、探测率、响应速度、抑制比等光电性能之间的内在联系和规律；获得优化的4H-SiC MESFET、BJT结构紫外光电晶体管的研制方案及其原型器件，为高增益的SiC光电晶体管的研制及其应用提供理论和实验基础。

紫外探测技术在军事和民用方面具有重要的应用价值，宽禁带半导体SiC材料是制备紫外探测器的优秀材料之一。鉴于无增益的SiC紫外光电二极管无法满足对微弱紫外光信号探测的应用需求，研制具有增益的SiC紫外探测器具有重要意义。目前，国内外在这方面的研究主要集中在SiC雪崩光电二极管的研制上，对同样具有增益的SiC紫外光电晶体管的深入研究却还没有。因此，本项目提出开展SiC紫外光电晶体管的基础问题研究，通过理论计算、模拟仿真、工艺实验等手段，揭示4H-SiC 材料基于MESFET、BJT 结构的紫外光电晶体管的工作机理；建立器件结构参数、SiC材料参数和工艺参数与器件的光增益、响应率、抑制比等光电性能之间的内在联系和规律；获得优化的4H-SiC MESFET、BJT结构紫外光电晶体管器件结构。同时，本课题对SiC光电晶体管器件研制的关键工艺进行研究和优化，主要包括SiC的ICP干法刻蚀，n型和p型SiC欧姆接触，SiC肖特基特性，以及SiC的热氧工艺，在此基础上，完成SiC光电晶体管的制备。器件的输出特性显示电流增益约为20，后续研究将在详细分析器件特性的结果之上，继续优化和改进SiC光电器件的结构设计和工艺，以获得特性良好的原型器件。