新型Ga2O3/SiC异质结增强型功率MOSFET研究

Among semiconductors, Si is the foundational technology against which all others are compared. Yet, as we approach the atomic limit of scaling for Si to reach the pinnacle of its performance, we see the fundamental limitations of its performance at the device level. There still remain applications and functions that are out of reach for this material. For power switching applications, the operating voltage is limited by the electric field strength at which breakdown occurs (Ebr) and minimum achievable background doping in epitaxial drift layers while minimizing total energy loss is limited by resistive power dissipation during on-state current conduction and capacitive loss during dynamic switching.These are fundamental performance limitations directly related to the Ebr of the material which is strongly correlated with the bandgap..As an emerging power electronics material with high critical electric field strength and large-area, native substrate availability, β-Ga2O3 offers significant cost and performance advantages over existing materials for switch applications. Industrial power applications based on high voltage operation are the initial primary motivation. However, There are obviously a large number of areas that need more development and improvements to fully demonstrate the advantages of β-Ga2O3l properties.These include the following:(1)Identification of the dominant defects in epitaxial films and the effect on device performance.(2)Experimental efforts to obtain p-type conductivity.(3)Interface state density mitigation processes for dielectrics for MOS devices.(4) thermal managemen tof Ga2O3 power electronics. .In this proposal, a nove structure of the enhanced power mosfet is proposedp with Ga2O3 / SiC Np Heterojunction to solve the problem of the p doping and Heat dissipation of the device. We will focus on the heterojunction physical model and high-performance insulated gate fabrication process to clarify the epitaxial thin film defects, heterojunction interface characteristics and MIS gate interface physical mechanism to obtainthe β-Ga2O3 heterojunction MOSFET precision model. Moerover, the optimized 600V, 5A prototype device will be designed and manufactureed to improve the performance of the device. The research of the project will provide theoretical and technical support for the research and development of new beta -Ga2O3 power devices.

宽禁带β-Ga2O3半导体材料以其高击穿场强优势，是高压低能耗功率器件的理想材料之一。目前，高质量β-Ga2O3薄膜制备以及高效绝缘栅材料可控生长和性能调控是面临的主要科学和技术障碍，加之p型β-Ga2O3掺杂难以实现和热导率低等材料劣势，使得β-Ga2O3功率器件的发展处于较低水平，其材料优势尚未体现。因此本项目创新的提出采用p型4H-SiC与β-Ga2O3形成异质pN结，解决β-Ga2O3无pn结和热导率差的问题，实现增强型功率MOSFET。重点研究异质结物理模型和高性能绝缘栅制备工艺，阐明外延薄膜缺陷，异质结界面特性和MIS栅界面物理机制，最终建立β-Ga2O3异质结MOSFET精准模型，设计制备出优化的600V，5A的原型器件，提高器件的性能。项目的研究将为β-Ga2O3新型功率器件的研发提供理论和技术支撑。

功率器件是能源系统中的核心部件，其电学性能直接决定了系统的能效，采用宽禁带半导体材料可以实现更小的导通电阻从而降低系统能耗。因此，β-Ga2O3半导体材料以其高击穿场强优势，是高压低能耗功率器件的理想材料之一。为了解决Ga2O3材料没有P型掺杂的难题，本项目围绕Ga2O3基异质结功率MOSFET器件开展了一系列研究，取得的结果如下：开发并掌握了Ga2O3/SiC, Ga2O3/NiO等异质结外延生长技术，在此基础上研究了外延薄膜中的缺陷产生以及演化机理，探索了缺陷对Ga2O3基功率器件、光电器件的影响；制备并分析了Ga2O3 MIS电容，包含HfO2、Al2O3等多种介质层的能带、电学以及可靠性分析，建立了Ga2O3基异质结功率器件模型，仿真研究了横向、纵向结构Ga2O3基异质结功率MOSFET器件，制备原型器件对上述模型和关键工艺进行了验证；依托本项目，已发表SCI论文14篇，其中ESI高被引1篇；申请中国发明专利5项；培养硕士研究生5名，已毕业2名；博士研究生3名，已毕业2名。