AlGaN基紫外双色探测器

In this project, for the application in the atmospheric sounding, we will fabricate the back-illuminated AlGaN based dual-band ultraviolet photodetectors by investigating the MOCVD growth of AlN and AlGaN layers, controlling stress, solving the p-doping in AlGaN materials and designing device structure. Firstly we must study the surface diffusion of Al atoms, reveal the dislocation formation process in AlN and AlGaN materials, and obtain high quality AlN and AlGaN materials by adjusting the growth parameters. Secondly, after controlling the stress of AlGaN materials, we will improve the p-AlGaN quality by using the p-AlGaN superlattice structure. Thirdly, we will solve the problem of p-AlGaN Ohmic contact by making use of the two-dimension hole gas formatted in the p-AlGaN superlattice materials, we also will investigate the device design and obtain the optimized structure parameters. Finally high performance AlGaN based dual-band ultraviolet photodetectors with the response wavelength of about 255nm and 296nm are realized .

本项目主要针对大气探测等应用需求，研究AlN和AlGaN材料的外延生长，实现应力调控，解决AlGaN材料的p型掺杂，设计新型器件结构，实现背照射AlGaN基紫外双色探测器。研究Al原子表面迁移过程，揭示AlN和AlGaN材料中位错的形成和湮灭机理，掌握抑制缺陷方法，生长出高质量的AlN和AlGaN材料；研究MOCVD生长中不同组分的AlGaN材料应力特性的变化，并实现应力调控；研究采取超晶格结构等方法，利用极化效应，减小受主杂质电离能，并研究杂质补偿机理和来源，控制补偿，提高p型掺杂效率；研究载流子的输运机理及其他输运过程，结合极化效应形成的二维空穴气等技术，解决p-AlGaN材料的欧姆接触问题。最后优化结构设计，研制出高性能的AlGaN基紫外双色探测器（~255nm和~296nm）。

本项目针对大气探测等需求，研究了AlGaN紫外双色探测器。自创了“复合缓冲层”结构，实现了无裂纹、高质量的AlN材料生长，其（002）、（102）面XRD半高宽仅为200弧秒，解决了国际难题；发现了碳杂质在p型中扮演施主角色，从而补偿受主、破坏p型，我们抑制了碳杂质实现了特性良好的p型(Al)GaN材料；我们还发现在p型层和金属界面处故意引入和调控碳杂质，可以增强载流子输运能力，从而解决了p型欧姆接触难题；研究了紫外探测器的漏电机理，发现控制材料的生长过程，有助于抑制孔洞缺陷，从而减小漏电，在大尺寸器件中得到了明显验证；研究并掌握了双色探测器的工艺技术，制备出AlGaN紫外双色探测器，还制备出紫外雪崩光电探测器。本项目研究成果为其他GaN基半导体器件也有重要参考作用。