高压IGBT的设计与实现及功率器件可靠性研究

发布时间：2018-06-12 02:20

本文选题：高压功率器件 + 绝缘栅双极晶体管　；参考：《浙江大学》2013年博士论文

【摘要】：IGBT作为最新一代的复合全控型功率器件,具有电压控制、输入阻抗大、驱动功率小、控制电路简单、开关损耗小、工作频率高等诸多优点,而高压IGBT在电机控制、新能源、轨道交通、智能电网、电动汽车等领域起着不可替代的作用。由于国内工艺技术水平相对落后,高压IGBT的设计与生产长期落后于国外。本课题旨在结合现有国内工艺,研发具有自主知识产权的高压IGBT芯片,为高压IGBT在国内的研发和实现积累一定的经验。功率器件可靠性问题已经成为影响功率模块整体性能的关键问题之一。本论文通过对功率器件SG-NLDMOS在热流子退化及关态雪崩击穿下的退化进行仿真与实验研究,揭示其退化机制,并提出改进措施。此项研究可为功率器件的可靠性设计及评估体系提供一定的参考价值。本论文的主要工作及创新点包括： 1、提出高压IGBT的设计方法,设计并实现了一款1700V/100A高压大电流NPT-IGBT,包括其元胞结构、终端结构、工艺流程及版图的设计。通过分析及仿真确定元胞的结构参数；采用场限环与场板相结合的终端结构,讨论场板的设置对终端结构的影响,提出多晶硅场板设置的方案；对IGBT背面的集电极工艺进行探索及优化；简化工艺流程,应用六块光刻版完成整个工艺流程；设计了栅电极置中的版图结构。 2、提出了双面N+扩散残留层的新结构来改善平面栅型IGBT的JFET电阻,在改善器件导通压降的同时,击穿电压没有发生显著的下降；把N+扩散残留层应用到沟槽栅型IGBT当中,提出了DR-IGBT的结构,并与传统的NPT-IGBT和LPT CSTBT进行比较。与传统的NPT-IGBT相比,在相同的击穿电压下,其导通压降与电流能力更优；与LPT CSTBT相比,击穿电压更高,而导通压降则在大电流密度下比LPT CSTBT更低；引入背面P-缓冲层,提出了NPN管辅助快速开关的IGBT(NFS-IGBT)新结构,具有更好的导通压降与关断时间的折衷。 3、采用中子嬗变掺杂的区熔单晶硅作为衬底,制作了多目标光刻版,流片完成后进行半桥模块的封装,并对IGBT器件进行了测试。击穿电压达到1700V以上,125℃下工作电流100A；阈值电压5.2V左右、栅发射极漏电流小于80nA、关断时间0.744μs、关断功耗25mJ,都达到设计要求,只是导通压降略高(3.7V)。 4、采用直流电压应力实验TCAD仿真、电荷泵测试,对SG-NLDMOS器件的热载流子效应进行研究,揭示热载流子效应与栅压相关,在中等栅压下,热载流子退化发生在积累区,界面态和氧化层陷阱电荷同时发生作用；在高栅压下,退化发生在侧墙区,界面态起主导作用；研究了结构参数Ndd对热载流子效应的影响,并提出了改善措施。采用电流脉冲应力实验、TCAD仿真和电荷泵测试,研究了SG-NLDMOS的关态雪崩击穿退化机制,发现雪崩击穿退化近似于高栅压和中等栅压下热载流子退化的叠加,氧化层陷阱正电荷主要产生于积累区,而界面态在整个漂移区中都有增加。
[Abstract]:As the latest generation of the composite full control power device, IGBT has the advantages of voltage control, large input impedance, small driving power, simple control circuit, small switching loss and high working frequency, and high voltage IGBT plays an irreplaceable role in the field of motor control, new energy, rail traffic, smart grid, electric vehicle and so on. The technical and technical level is relatively backward, the design and production of high voltage IGBT lag behind the foreign countries for a long time. This topic aims to develop high voltage IGBT chips with independent intellectual property in combination with existing domestic technology, and accumulate certain experience for the research and development and Realization of high voltage IGBT in China.
The reliability of power devices has become one of the key problems that affect the overall performance of power modules. Through the simulation and experimental study of the degradation of the power device SG-NLDMOS under the heat flux degradation and the close state avalanche breakdown, the degradation mechanism is revealed and the improvement measures are put forward. This study can be used for the reliability of power devices. It provides a certain reference value for the evaluation system.
The main work and innovation of this paper include:
1, the design method of high voltage IGBT is put forward, and a 1700V/100A high voltage and large current NPT-IGBT is designed and implemented, including its cellular structure, terminal structure, process flow and layout design. The structure parameters of the cell are determined by analysis and simulation, and the terminal structure combining field limit ring and field plate is adopted to discuss the terminal structure of the field plate. The scheme of setting the polysilicon field board is proposed, and the collector process on the back of IGBT is explored and optimized; the process flow is simplified, the whole process flow is completed with six lithography plates, and the layout structure of the grid electrode is designed.
2, a new structure of the double-sided N+ diffusion residual layer is proposed to improve the JFET resistance of the plane gate type IGBT. The breakdown voltage is not significantly reduced while the device's conduction pressure drop is improved; the N+ diffusion residual layer is applied to the groove gate IGBT, and the structure of the DR-IGBT is proposed and compared with the traditional NPT-IGBT and LPT CSTBT. Compared with the NPT-IGBT, the pressure drop and current capacity are better under the same breakdown voltage, and the breakdown voltage is higher than that of LPT CSTBT, while the conduction pressure drop is lower than that of LPT CSTBT at the large current density; the back P- buffer layer is introduced, and a new IGBT (NFS-IGBT) structure with the auxiliary fast switch of the NPN tube is proposed, which has a better conduction pressure drop and a better conduction pressure drop. The tradeoff between closing time.
3, the multi target photolithography plate is made with the neutron transmutation doped monocrystalline silicon as substrate. After the flow sheet is completed, the half bridge module is encapsulated, and the IGBT device is tested. The breakdown voltage is above 1700V, the working current is 100A at 125 C, the threshold voltage is about 5.2V, the gate emitter leakage current is less than 80nA and the closing time is 0.744 U S. The power consumption of 25mJ is up to the design requirement, but the conduction voltage drop is slightly higher (3.7V).
4, a DC voltage stress experiment TCAD simulation, a charge pump test, is used to study the hot carrier effect of the SG-NLDMOS device. It is revealed that the hot carrier effect is related to the gate pressure. Under the middle gate pressure, the thermal carrier degradation occurs in the accumulating area, and the interface state and the oxide trap charge are simultaneously affected, and the degradation occurs at the side wall under the high gate pressure. The influence of the structure parameter Ndd on the hot carrier effect is studied and the improvement measures are proposed. The breakdown mechanism of the close state avalanche in SG-NLDMOS is studied by the current pulse stress experiment, the TCAD simulation and the charge pump test. It is found that the avalanche breakdown and deionization are approximate to the high gate pressure and the middle gate pressure drop back. The superposition of the oxide trap is mainly due to the accumulation of positive charges, while the interface state increases in the drift region.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TN322.8

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