蓝宝石衬底上低位错密度、低残留应变AlN薄膜外延生长研究

AlGaN基深紫外LED在杀菌消毒、印刷和非视距通信等领域拥有巨大的应用前景，而高质量AlN外延薄膜是制备高电光转换效率、高可靠性深紫外器件的基础与关键。纳米图形化衬底侧向外延在高质量AlN外延领域优势明显，但仍存在位错增殖控制和残留应变调控的不足。本项目以获得纳米图形化衬底上低位错密度、低残留应变AlN薄膜为目标，提出采用高晶体取向一致性纳米图形化AlN模板（NPAT）调控AlN晶柱晶体取向差异，减少位错增殖数量，并采用分步式合拢引入额外自由面，弯转控制增殖位错和高效弛豫薄膜应力的创新思路，系统开展NPAT上AlN外延生长动力学、缺陷控制和应变调控规律研究。在此基础上，制备位错密度低于5 E+7/cm2、残余应力低于0.2 GPa的高质量AlN外延薄膜，并实现器件验证。本项目研究内容是当前国际氮化物半导体研究领域的热点之一，可为高性能深紫外LED的制备提供理论和技术指导，推动其产业发展。

AlGaN-based deep ultraviolet LED has a great application prospect in sterilization, printing and non-horizon communication, and high-quality AlN epitaxial film is the basis and key for the preparation of deep ultraviolet devices with high wall-plug efficiency and high reliability. Epitaxial lateral overgrowth of AlN on nano-patterned substrate has obvious advantages in the field of high-quality AlN epitaxy, but it still has shortcomings in the control of dislocation generation and residual strain. In order to obtain AlN film with low threading dislocation density and residual strain on nano-patterned substrate, this project will creatively adopt high crystal orientation consistency nano-patterned AlN template (NPAT) to regulate crystal orientation difference of AlN crystals, reducing the generation of dislocation, and introduce additional free surface from step-by-step AlN column coalescence to control dislocation and residual strain of AlN film, then study AlN epitaxial growth kinetics, defect control and strain regulation laws on the NPAT systematacially. On this basis, this project can obtain high-quality AlN films with dislocation density less than 5 E+7/cm2 and residual stress less than 0.2 GPa, and realize device preparation on the AlN film. The research content of this project is one of the hot spots in the current international nitride semiconductor research field, which can provide theoretical and technical guidance for the preparation of high-performance deep ultraviolet LED and promote its industrial development.