GaN材料是适合高频、高功率密度应用的优良半导体材料，但目前高压GaN器件的最大耐流均较低，极大地限制了其在电动汽车、船舶、飞机等追求高效、高功率密度的大功率移动式微网中的使用。本项目拟实现一种基于耗尽型GaN晶体管并联的650V，N*50A（N=2~6）的共源共栅型功率模块，该模块仅需一个驱动芯片，即可实现现有高压GaN产品2倍及以上的通流能力，可有效增大功率密度、提高效率和减少成本。本项目将围绕功率模块设计展开以下研究内容：建立可推广的功率模块精确解析模型；定义并计算并联电流的不均衡度，探索均流策略；分析不稳定现象机理，提出稳定判据与抑制方法；确定最优并联数，优化布局与引线键合方式，最终完成综合性能最佳的功率模块，并总结出适用于具有不同组合参数的功率模块的通用设计方法。本项目研究不仅为GaN器件应用于大电流场合提供了重要的理论依据和技术方案，更可为同类型的负压关断型器件的扩流提供指导。

Gallium Nitride (GaN) materials have the advantageous properties, including high critical field, wide band gap, high electron mobility, etc., which are suitable for high frequency, high voltage, high temperature and high power density occasions. However, at present, the maximum current allowed of discrete high voltage GaN devices is relatively low, and it is difficult to achieve improvement in the short term through the manufacture process, greatly limiting the use of GaN devices in high power mobile microgrids, like electric vehicles, ships and aircrafts which pursue high efficiency and high power density.. This project intends to realize a novel 650V, N*50A (N=2~6) cascode GaN power module based on the paralleling of depletion-mode GaN transistors. The proposed cascode GaN power module can withstand twice or more the current than original cascode GaN HEMT using only one gate driver, which increases the power density, improves the system efficiency and saves the cost. The project will carry out the following research focusing on a series of key issues in the design of proposed GaN power module: build the general high-frequency matrix of parasitics and the accurate analytical model of GaN power module, taking into account all the parasitic parameters including their nonlinearity, mutual inductances and temperature characteristic; define and calculate the unbalanced degree of parallel currents, divide the safe parallel operation region with respect to the range of parasitic parameters, and propose corresponding strategies to balance the current from the aspects of layout and internal bonding; analyze the mechanism of instability in the proposed GaN power module, define the stability criterion and provide suppression methods; make trade-off between the maximum current, on resistance, gate charge, junction temperature and other parameters of power module to choose an optimized parallel number, adopt effective current balancing strategies and suppression methods of instability, optimize the internal configuration and wire bonding of package, finally complete a GaN power module with the best overall performance and summarize a general design method applicable to cascode GaN power module with different parameters of Si MOSFETs and depletion-mode GaN transistors. The research of this project will not only provide important theoretical bases and technical solutions for the application of GaN devices in high current occasions, but also fill the vacancies in the related research fields of GaN, and meanwhile, offer critical guidance for increasing the current capability of similar devices turning off at negative voltage.