4H-SiC肖特基二极管及结终端技术研究

发布时间：2018-05-18 18:36

  本文选题：4H-SiC + SBD　； 参考：《河北工业大学》2015年硕士论文

【摘要】：采用宽禁带半导体材料4H-SiC制作的肖特基势垒二极管SBD具有PN结二极管无法比拟的优越特性。国外对4H-SiC材料及其器件的研制和分析已经有了诸多报道,而国内在这方面的研究起步较晚,研究成果的相关报道较少。因此开展4H-SiC SBD器件研究有重要的意义。在此背景下,本文对4H-SiC SBD器件的主要电学特性进行了系统研究,主要研究成果如下:1、为了解决由于4H-SiC SBD器件近表面的电场集边效应造成的器件击穿特性变差的问题,采用加入结终端结构的方法来降低器件近表面的强电场,提高器件的击穿电压。在掌握结终端结构分类的基础上,确定采用延伸型终端结构来优化4H-SiC SBD器件的反向击穿特性。2、实现加入不同结终端结构的器件仿真。利用Silvaco TCAD软件对器件进行仿真。首先仿真了加入两级场限环结构的4H-SiC SBD器件,该结构的敏感参数有环间距、环的注入结深和环区掺杂浓度,仿真确定的最优值环间距为3μm,结深为0.4μm,掺杂浓度为1×1017cm-3,环宽为10μm,此时器件的击穿电压为1200V。针对场限环结构对器件界面电荷很敏感的问题,在场限环结构基础上,仿真了加入场板结构的器件特性,场板结构的敏感参数为场板长度,仿真确定其最优值为20μm,此时器件的击穿电压可到达1350V。然后仿真了加入结终端扩展JTE结构的器件,该结构的敏感参数有JTE结构长度,注入结深和掺杂浓度,仿真确定其最优值长度为30μm,结深为1.0μm,掺杂浓度为1×1018cm-3,在此情况下器件的击穿电压达到1500V。3、通过对比加入不同结终端结构器件的模拟仿真结果,可以看出与两级场限环结构器件以及场限环和场板复合结构器件相比,加入JTE结构的器件击穿特性更好。因此实验制作了加入JTE结构的4H-SiC SBD器件。二次离子质谱法SIMS测试得到实验器件JTE结构区Al离子在0.9μm范围内的掺杂浓度为1018cm-3量级;Keithley4200半导体参数测试仪测试了器件的正反向电流-电压特性曲线,得到器件在正向电流为0.7A时开启电压为0.9V,反向漏电流为10μA时击穿电压为1200V;从器件的反向恢复特性曲线可知器件的反向恢复时间仅为25ns。
[Abstract]:The Schottky barrier diode SBD made with wide band gap semiconductor material 4H-SiC has superior characteristics which can not be compared with PN junction diode. There have been many reports on the development and analysis of 4H-SiC materials and their devices abroad. The domestic research in this field is late and the related reports of the research results are less. Therefore, the 4H-SiC SBD device is carried out. In this context, the main electrical characteristics of 4H-SiC SBD devices are systematically studied in this paper. The main research results are as follows: 1, in order to solve the problem that the breakdown characteristics of the device caused by the edge effect of the electric field in the near surface of the 4H-SiC SBD device is poor, the method of joining the junction terminal structure is used to reduce the device. A strong electric field near the surface improves the breakdown voltage of the device. On the basis of the classification of the terminal structure, the extension type terminal structure is used to optimize the reverse breakdown characteristic of 4H-SiC SBD device, and the device simulation with different junction terminal structures is realized. The device is simulated with the Silvaco TCAD software. First, the simulation is added to the two stage. 4H-SiC SBD device with field limiting ring structure, the sensitive parameters of the structure are ring spacing, injection depth of ring and doping concentration in the ring region. The optimal ring spacing is 3 u m, the depth is 0.4 m, the doping concentration is 1 x 1017cm-3 and the ring width is 10 u m. At this time, the breakdown voltage of the device is 1200V. sensitive to the interface charge of the device. On the basis of the presence limit loop structure, the device characteristics added to the field plate structure are simulated. The sensitive parameter of the field plate structure is the field plate length. The simulation determines that the optimal value is 20 u m. At this time the breakdown voltage of the device can reach 1350V. and then simulates the device with the junction terminal to expand the JTE structure, and the sensitive parameter of the structure has the JTE structure length. With the injection depth and doping concentration, the optimum length is 30 mu m, the depth is 1 mu m and the doping concentration is 1 x 1018cm-3. Under this condition, the breakdown voltage of the device reaches 1500V.3. By comparing the simulation results of different junction terminal structure devices, it can be seen that it is combined with the field limiting ring structure and the field limit ring and the field plate. Compared with the structure device, the device with JTE structure has better breakdown characteristics. Therefore, the experiment made the 4H-SiC SBD device with the JTE structure. The two ion mass spectrometry SIMS test obtained the doping concentration of the Al ion in the JTE structure area of the experimental device in the range of 0.9 mu m, and the Keithley4200 semiconductor parameter tester tested the positive and negative of the device. To the current voltage characteristic curve, the breakdown voltage is 1200V when the positive current is 0.7A and the reverse leakage current is 10 A. The reverse recovery time of the device is only 25ns. from the reverse recovery characteristic curve of the device.
【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN311.7
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本文编号：1906744