【摘要】 本文设计了一种具有低Al组分p型渐变AlxGa1-xN层和高/低Al组分AlGaN倍增层的背入射式p-i-n-i-n吸收倍增区分离的特殊AlGaN日盲紫外雪崩光电二极管（Avalanche Photodiode,APD）,并插入AlN/Al_0.64 Ga_0.36N分布式布拉格反射器来改善APD的日盲响应。为了在实验条件下生长出特殊设计的AlGaN APD,用Atlas-Silvaco仿真软件对该器件结构进行仿真,并用常规结构APD作为参照。研究结果表明,特殊设计的APD比常规的APD表现出更好的光电特性。由于设计的APD拥有更高的空穴碰撞电离系数并同时产生了与外加电场同方向的高极化电场,所以相比于常规的APD,本文设计的APD的雪崩倍增增益为6.11×10⁴,提高了10倍,同时雪崩击穿电压显著降低。设计的APD的光电特性良好,为生长AlGaN基APD提供了坚实的理论基础。更多还原

【Abstract】 A back-illuminated p-i-n-i-n separate absorption and multiplication（SAM）solar-blind ultraviolet AlGaN avalanche photodiode（APD）with a low-Al-content p-graded Alx Ga1-xN layer and a high/lowAl-content AlGaN multiplication layer was designed. Simultaneously,an AlN/Al_0.64 Ga_0.36N distributed Bragg reflector（DBR）structure was inserted to improve the solar-blind photo-response of the designed APD. To fabricate a specially designed AlGaN APD under experimental conditions,the rationality of the device structure needs to be verified in advance. Therefore,the designed APD was simulated using AtlasSilvaco simulation software,and a conventional APD structure was used as a reference. The simulation results indicate that the designed APD exhibits enhanced optoelectronic characteristics in comparison to a conventional APD,which is attributed to the higher hole-initiated impact ionization coefficient and polarization electric field generated in the same direction as the applied bias field of the designed APD. The designed APD exhibits a 10-fold avalanche gain,which is 6. 11×10⁴,and reduced avalanche breakdown voltage compared with a conventional APD. Moreover,the designed APD exhibits good optoelectronic characteristics,and will provide a solid theoretical basis for the further development of AlGaN-based APDs.更多还原