Si衬底上氮化物半导体异质结构材料和功率电子器件相关物理问题研究

Semiconductor power electronic devices are playing an important role in industry control, new energy power generation, electric vehicles, power grid and consumer electronics, etc. With its advantageous material properties, AlGaN/GaN heterostructure based power electronic devices are considered to be excellent candidates for the next generation high efficient and high power switching applications due to the promising energy saving capability comparing with Si devices. In this project, utilizing the vast buildup of technical know-how and solid understanding of fundamental physics on GaN-based heterostructure materials and devices by Peking University and Institute of Microelectronics of Chinese Academy of Sciences, we aim at solving key physical problems in material and devices on GaN-on-Si platform for power applications, including: (1) revealing the growth dynamics, stress and defect control in MOCVD epitaxy growth of GaN-based.heterostructures; (2) understanding the behavior of C-related localized electronic states and the effect on device performance; (3) understanding the high field transport properties of 2DEG in GaN-based heterostructures and the energy/momentum relaxation mechanism of hot electrons; (4) revealing the occupancy condition of surface states on AlGaN barrier and interface states in gate-recessed MIS structures under high electric fields, and the relationship with static and dynamic characteristics of power devices. Through the above efforts, we will make the well understanding on the physical mechanism influencing the performance of GaN-based materials on Si substrates and the power electronic devices and developing the corresponding control method, which would provide scientific basis.for enhancement of the epitaxy material quality and device performance and reliability. Meanwhile, the project would ultimately promote the commercialization of GaN-based power electronic devices and a group of outstanding young talents in this field would emerge after the project through training.

基于GaN基异质结构的功率电子器件的节能特性比之Si器件优势明显，有望在下一代高效功率电子器件领域广泛利用。本申请项目结合北京大学和中科院微电子所在GaN基异质结构物理、材料和器件研究上的工作积累和优势，共同致力于Si衬底GaN基异质结构和功率电子器件面临的关键物理问题的研究和解决，主要包括（1）Si衬底GaN基异质结构的外延生长动力学及其应力和缺陷控制、（2）高阻GaN外延层中碳杂质相关局域态特性及其对器件性能的影响、（3）GaN基异质结构2DEG的高场输运性质和热电子能量/动量弛豫机制、（4）AlGaN势垒层表面态及MIS结构界面态在强电场下的占据行为及其与器件静态/动态特性的关联。通过上述工作，基本理解和掌握影响Si衬底GaN基异质结构性质和功率电子器件性能的物理机制和调控方法，为改善GaN基异质结构材料外延生长质量和提高功率电子器件性能及可靠性提供物理依据，并推动其实用化进程。

自2017年起，本项目按照计划任务书的要求主要开展了三方面的研究工作：（1）Si衬底上GaN薄膜及其异质结构的外延生长规律及方法，（2）GaN及其异质结构中杂质、缺陷和界面态物理性质及控制规律，（3）Si衬底上GaN基高性能功率电子器件研制及器件物理。经过项目组全体成员5年来的共同努力，在高质量GaN基薄膜及其异质结构的外延生长和缺陷控制、GaN中C、H等杂质的物理性质和控制方法、GaN基高电子迁移了率晶体管（HEMT）界面态特性及其抑制方法、高性能增强型GaN基功率电子器件研制等方面取得了一系列进展和突破，全面超过了计划任务书规定的材料和器件性能指标。5年来本项目共发表标有项目号的SCI收录论文40篇，包括Physical Review Letters 1篇、Advanced Functional Materials 1篇、ACS Applied Material Interfaces 2篇、本领域主流期刊IEEE Electron Device Letters 8篇、Applied Physics Letters 13篇，编著本领域中文专著2部，英文专著2部，申请国家发明专利22件(其中已授权7件)。5年来项目组成员在国内外学术会议上做大会邀请报告10次，分会邀请报告15次，研究成果在国内外同行中产生了广泛影响，项目负责人作为第一完成人的“氮化物半导体大失配异质外延技术”成果获得了2018年度国家技术发明二等奖。5年来，项目组有1人获得国家优秀青年科学基金，出站博士后3人，毕业博士研究生10人、硕士研究生7人。本项目成果也获得了产业界的高度重视，相关成果与华为等高技术企业签订了产业化研发协议，部分成果实现了技术转让和产业化落地。总之，本项目圆满完成了计划任务书规定的各项研究任务，为我国宽禁带半导体物理学的发展做出了贡献，并促进了我国第三代半导体技术和产业的发展。