GCT横向变掺杂（VLD）结终端结构的优化设计

发布时间：2018-11-13 19:09

【摘要】：集成门极换流晶闸管(IGCT)作为一个新型的电力半导体器件,广泛的应用于大功率领域。阻断电压及其稳定性是衡量器件阻断能力和可靠性的一个非常重要的标志,为了提高GCT的阻断电压及其稳定性和芯片利用率,需要对其结终端结构进行优化设计。本文以4.5kV GCT为例,提出了一种横向变掺杂(VLD)结终端结构的设计方法。首先利用Sentaurus-TCAD仿真软件,重点对VLD结终端结构的耐压机理及击穿特性进行研究,提取合适的终端结构参数,其次对比分析了钝化层中的电荷对器件击穿特性的影响,最后对GCTVLD结构的关键制作工艺进行了分析。主要研究内容如下:第一,分析了 VLD的结构特点及传统设计思路,提出了一种更为简便的终端掩模设计方法。采用此方法设计了一款GCT终端结构,并采用Sentaurus-TCAD软件进行了仿真验证。结果表明,VLD结构在耐压效率、稳定性及终端尺寸方面均优于传统的台面斜角终端及普通的场限环终端结构,并对终端结构参数进行了优化设计。第二,研究了 VLD终端结构的钝化膜。分析了钝化层中固定电荷对击穿电场强度分布及击穿电压的影响。结果表明,钝化层中固定电荷的极性(正、负)及密度Qss的大小对终端击穿特性有很大的影响,并且当其中固定电荷密度大于1 × 109cm2时不适用于VLD结终端结构。第三,研究了 GCTVLD的关键工艺。根据优化设计的VLD掩模参数,通过工艺仿真给出的VLD掺杂剖面具体的工艺实施方案,并对GCT VLD结构的阻断特性进行了仿真验证,结果验证了本文所提出的设计方法的可行性。本文的研究成果对高压深结器件的结终端结构设计具有一定的参考价值。
[Abstract]:As a new type of power semiconductor device, integrated gate commutation thyristor (IGCT) is widely used in high power field. The blocking voltage and its stability are very important indicators to measure the blocking ability and reliability of the device. In order to improve the blocking voltage, stability and chip utilization of GCT, it is necessary to optimize the design of the junction terminal structure. Taking 4.5kV GCT as an example, this paper presents a design method for the terminal structure of transversely variable doped (VLD) junctions. Firstly, by using Sentaurus-TCAD simulation software, the voltage resistance mechanism and breakdown characteristics of the terminal structure of the VLD junction are studied, and the appropriate terminal structure parameters are extracted. Secondly, the influence of the charge in the passivation layer on the breakdown characteristics of the device is compared and analyzed. Finally, the key fabrication process of GCTVLD structure is analyzed. The main contents are as follows: first, the structure characteristics and traditional design ideas of VLD are analyzed, and a more convenient design method of terminal mask is proposed. A GCT terminal structure is designed with this method, and the simulation is carried out by Sentaurus-TCAD software. The results show that the VLD structure is superior to the traditional bevel terminal and the common field limiting loop terminal structure in voltage efficiency, stability and terminal size. The structure parameters of the terminal are optimized. Secondly, the passivation film of VLD terminal structure is studied. The influence of fixed charge in passivation layer on the distribution of breakdown electric field and breakdown voltage is analyzed. The results show that the polarity (positive, negative) and density Qss of the fixed charge in the passivation layer have great influence on the breakdown characteristics of the terminal, and it is not suitable for the terminal structure of the VLD junction when the fixed charge density is greater than 1 脳 109cm2. Thirdly, the key technology of GCTVLD is studied. According to the optimized VLD mask parameters, the specific process implementation scheme of VLD doping profile is given by process simulation, and the blocking characteristics of GCT VLD structure are verified by simulation. The results verify the feasibility of the design method proposed in this paper. The research results in this paper have certain reference value for the design of junction terminal structure of high voltage deep junction device.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN34

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