250V抗辐射VDMOS的研究与设计

发布时间：2018-04-11 20:59

本文选题：抗辐射 + VDMOS　；参考：《东南大学》2015年硕士论文

【摘要】：应用于航天器领域的VDMOS器件受到辐射会产生总剂量辐射电离效应(TID),从而使得器件出现阂值电压漂移、导通电阻变化和击穿电压下降等现象,这些现象会极大地影响VDMOS器件的性能、进而导致航天器寿命下降。同时,辐射也会产生单粒子效应(SEB、SEGR)使得VDMOS器件烧毁失效。因此,对VDMOS器件辐射加固方法的研究意义重大。本文在普通VDMOS器件的基本结构、主要参数等基础上重点研究了辐射产生的三种效应,即SEB、SEGR和TID。借助TSUPREM4、MEDICI,研究了VDMOS器件发生SEB、SEGR失效的过程,揭示了VDMOS器件产生SEB、SEGR的物理机理。通过分析器件漏源击穿特性曲线,得出了VDMOS器件二次击穿点电压与SEB安全工作区域的关系。通过分析器件电场纵向分布和净剩电荷纵向分布,提出了用电荷曲线积分原理解释VDMOS器件电场纵向分布的方法。借助SEGR半经验公式,建立了SEGR分析模型,并用该模型研究了离子种类、入射位置、JFET区宽度对VDMOS器件发生SEGR的临界条件的影响,分别得出辐射离子原子序数越大越容易发生SEGR、入射位置越靠近JFET区中间越易发生SEGR、 JFET区宽度越窄越有利于器件抵抗SEGR的结论。然后,重点分析了VDMOS器件抗SEB、SEGR的辐射加固方法,研究了P+/N+工艺参数对VDMOS器件SEB安全电压的影响,得出P+与N+浓度相差越大SEB安全电压越小的结论。通过比较带缓冲层和不带缓冲层两种结构SEB安全电压的大小,证实了带有缓冲层的结构有利于抗SEB的结论,并利用MEDICI仿真给出了缓冲层的最佳参数。最后,提出了一种新型抗SEGR的VDMOS器件结构,比较了新型结构和传统结构的SEGR临界条件,证实了该结构抗SEGR性能良好的结论。本文完成了课题的设计目标：250V/12A、导通电阻0.22Ω、阈值电压2-4V的抗辐射VDMOS器件。借助TSUPREM4和MEDICI软件软件设计了器件的电学参数、确定了最终的工艺流程,并利用Cadence软件绘制了不同方案的器件版图。仿真结果表明器件设计满足指标要求。
[Abstract]:The ionizing effect of total dose radiation on the VDMOS devices used in spacecraft field will be caused by the total dose radiation ionization effect, which will lead to the threshold voltage drift, the change of on-resistance and the decrease of breakdown voltage, etc.These phenomena will greatly affect the performance of VDMOS devices and lead to the decline of spacecraft life.At the same time, the single particle effect is also produced by the radiation, which causes the VDMOS device to burn out.Therefore, it is of great significance to study the radiation reinforcement method of VDMOS devices.In this paper, based on the basic structure and main parameters of VDMOS devices, three kinds of radiation effects, namely SEBX SEGR and TID, are studied.By means of TSUPREM4 MEDICI, the failure process of VDMOS devices is studied, and the physical mechanism of SEBU SEGR generation by VDMOS devices is revealed.The relationship between the secondary breakdown point voltage of VDMOS device and the safe working area of SEB is obtained by analyzing the breakdown characteristic curve of the device drain source.Based on the analysis of the longitudinal distribution of electric field and net residual charge of VDMOS devices, a method to interpret the longitudinal distribution of electric field in VDMOS devices by means of charge curve integral principle is proposed.Based on the SEGR semi-empirical formula, the SEGR analysis model is established, and the influence of ion species, incident position and JFET width on the critical conditions for SEGR occurrence in VDMOS devices is studied.It is concluded that the larger the atomic number of the radiation ions, the easier the SEGRs are, the closer the incident position is to the middle of the JFET region, the easier the SEGRs are, and the narrower the width of the JFET region is, the more favorable the device is to resist the SEGR.Then, the radiation reinforcement method of VDMOS device is analyzed, and the influence of P / N process parameters on the safe voltage of VDMOS device SEB is studied. The conclusion is drawn that the greater the difference between P and N concentration is, the smaller the S EB safe voltage is.By comparing the security voltage of SEB with and without buffer layer, the conclusion that the structure with buffer layer is favorable to resist SEB is confirmed, and the optimum parameters of buffer layer are given by MEDICI simulation.Finally, a new type of VDMOS device structure is proposed to resist SEGR. The SEGR critical conditions of new structure and traditional structure are compared, and the conclusion that the structure has good anti-#en3# performance is proved.In this paper, the objective of the design is: 250V / 12A, on-resistance 0.22 惟, threshold voltage 2-4V anti-radiation VDMOS device.The electrical parameters of the device are designed with the help of TSUPREM4 and MEDICI software, the final process is determined, and the device layout of different schemes is plotted by using Cadence software.The simulation results show that the device design meets the requirements.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN386

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