4H-SiC晶闸管电荷调制JTE的研究

发布时间：2018-04-16 09:29

本文选题：碳化硅 + 电荷调制结终端　；参考：《西安理工大学》2017年硕士论文

【摘要】：4H-SiC晶闸管以其耐压高、通态压降小、通态功耗低等优点在特大功率的工频开关应用,尤其是高压直流输电(high voltage DC,HVDC)中具有较大优势。高效的结终端结构设计是实现超高压晶闸管的一大挑战。本文针对20kV4H-SiC晶闸管提出一种称为电荷调制JTE的新型终端结构,该终端仅需两步离子注入便可形成具有电荷调制功能的三区JTE结构。运用Silvaco软件对新型终端进行了仿真研究,结果表明,该终端不仅具有高的耐压能力,而且减小了击穿电压对JTE区剂量的敏感度,增加了工艺鲁棒性。主要研究内容和结果如下:首先仿真研究了 4H-SiC晶闸管台面结终端,台面+JTE结终端以及台面+三区JTE结终端三种终端技术,得到各终端的主要结构参数与器件击穿特性之间的优化关系,为新终端的提出奠定了一定的基础。第二,提出一种新型的电荷调制JTE终端,理论分析了其耐压机理。通过仿真手段优化JTE中调制环的环间距、环个数等参数使器件击穿特性达到最优。最终获得26.24kV的高耐压值,且击穿电压在整个有效剂量区保持稳定。研究光刻偏差对器件击穿特性的影响,结果显示光刻工艺偏差在2μm之内时,击穿电压变化甚小,说明了两步离子注入工艺制作电荷调制JTE的可行性。第三,通过对比新型终端和单区JTE,三区JTE的终端效率,工艺容差,界面电荷影响几个方面来说明新型终端的高效性。结果显示相比于其他两种终端,新型终端的电场分布均匀,其终端效率最高可达99%;拥有更优的工艺容差特性,耐压在一个宽的剂量范围11.9×1012cm-2内可以维持在90%的理想击穿电压以上;击穿电压对界面电荷敏感度降低,当面电荷密度为-2×10121m-2时,击穿电压仅下降了 0.9%。本文的研究结果对研发新型结终端结构、提高器件耐压及可靠性提供了有益的参考。
[Abstract]:The 4H-SiC thyristor has the advantages of high voltage resistance, low on-state voltage drop and low on-state power consumption, especially in the application of high-voltage direct current transmission (HVDC) high voltage DC.Efficient junction terminal structure design is a major challenge to the realization of UHV thyristors.In this paper, a novel terminal structure called charge modulated JTE is proposed for the 20kV4H-SiC thyristor. The terminal can form a three-zone JTE structure with charge modulation function by only two steps of ion implantation.The Silvaco software is used to simulate the new terminal. The results show that the terminal not only has high voltage resistance, but also reduces the sensitivity of breakdown voltage to the dose of JTE, and increases the process robustness.The main contents and results are as follows: firstly, three terminal technologies of 4H-SiC thyristor Mesa junction terminal, Mesa JTE junction terminal and Mesa three area JTE junction terminal are simulated.The optimized relationship between the main structure parameters of each terminal and the breakdown characteristics of the device is obtained, which lays a foundation for the new terminal.Secondly, a novel charge modulated JTE terminal is proposed and its voltage resistance mechanism is analyzed theoretically.By means of simulation, the parameters such as the ring spacing and the number of rings in JTE are optimized to optimize the breakdown characteristics of the device.Finally, the high voltage value of 26.24kV was obtained, and the breakdown voltage remained stable in the whole effective dose range.The effect of lithography deviation on the breakdown characteristics of the device is studied. The results show that the breakdown voltage changes very little when the lithography process deviation is less than 2 渭 m, which shows the feasibility of making charge modulated JTE by two-step ion implantation process.Thirdly, the efficiency of the new terminal is illustrated by comparing the terminal efficiency, process tolerance and interface charge of the new terminal with that of the single-zone JTE and the three-zone JTE.The results show that compared with the other two terminals, the electric field distribution of the new terminal is uniform, and the terminal efficiency can reach the maximum of 99. The terminal has better process tolerance, and the voltage resistance can be maintained above 90% of the ideal breakdown voltage in a wide dose range of 11.9 脳 1012cm-2.When the charge density is 2 脳 10121m-2, the breakdown voltage decreases only 0.9.The results of this paper provide a useful reference for the research and development of a new junction terminal structure and improve the voltage resistance and reliability of the 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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