高压雪崩二极管的研究

发布时间：2018-07-11 10:02

本文选题：雪崩击穿耐量 + 缓冲层　；参考：《沈阳工业大学》2015年硕士论文

【摘要】：近年来功率半导体器件的应用已经拓展到各个领域，对于器件的可靠性要求越来越严格。而在大功率应用中，高压二极管作为维持功率器件稳定运行的基本单元，其自身的耐用性显得十分重要。在一些场合需要功率二极管工作在雪崩击穿模式下，因此功率二极管应具有一定的雪崩耗散能量（本文称雪崩击穿耐量）。如何提高高压功率二极管的雪崩击穿耐量是目前国内外在功率器件研究领域的新课题。本文以提高功率二极管的雪崩击穿耐量为目标，设计耐压2300V的高压雪崩二极管。本文的核心思想是在对高压雪崩二极管的雪崩击穿特性进行理论和仿真分析的基础上，，分析雪崩损坏机制，总结具有提高雪崩击穿耐量的结构，并对主要结构进行仿真分析和优化设计。首先，从一般高压二极管结构入手，借助Silvaco-TCAD仿真软件对二极管在反向击穿情况下的电场分布进行仿真和理论分析，高压雪崩二极管工作在雪崩击穿模式时，随雪崩击穿电流的增加，电场分布的形式发生了改变，当雪崩击穿电流增加到一定值时，在阴极侧nn+结处出现的二次电场尖峰，这是引发双雪崩效应并导致器件损坏的主要原因。通过在n-区与n+区之间引入缓冲层结构可抑制nn+结处二次电场尖峰的出现，提高雪崩击穿耐量。最后根据设计指标对带有缓冲层的二极管进行优化设计。首先对非穿通结构与穿通结构进行阻断参数设计，耐压为2300V的非穿通结构与穿通结构二极管基区参数分别为：非穿通结构基区掺杂浓度ND=6.1×1013cm-3，基区宽度WN=280μm；穿通结构基区掺杂浓度ND=1.87×1013cm-3，基区厚度WN=160μm。在此结构参数先对雪崩击穿耐量进行了分析，单纯从雪崩击穿耐量来看，非穿通结构更有利于雪崩耐量的提高，但考虑在高压领域导通压降的重要性，选择穿通结构加入缓冲层进行高压雪崩二极管的设计，均衡导通压降与雪崩击穿耐量的考虑，对缓冲层厚度与浓度进行优化。缓冲层的参数为：缓冲层厚度d=15μm；缓冲层浓度Nbuffer=3×1014cm-3。通过对具有缓冲层结构的高压雪崩二极管进行仿真分析，结论是缓冲层可以有效地降低阴极侧的电场尖峰，延缓了负微分电阻的出现，从而提高了雪崩击穿耐量。
[Abstract]:In recent years, the application of power semiconductor devices has been expanded to various fields, and the reliability requirements of the devices are becoming more and more stringent. In high power applications, high voltage diodes, as the basic unit to maintain the stable operation of power devices, its durability is very important. In some cases, power diodes are required to work in avalanche breakdown mode, so the power diodes should have a certain avalanche dissipation energy (in this paper, avalanche breakdown tolerance). How to improve the avalanche breakdown tolerance of high voltage power diodes is a new topic in the field of power device research at home and abroad. In order to improve the avalanche breakdown tolerance of power diodes, a 2300V high voltage avalanche diode is designed in this paper. The core idea of this paper is to analyze the mechanism of avalanche damage on the basis of theoretical and simulation analysis of avalanche breakdown characteristics of high voltage avalanche diodes. And the main structure of simulation analysis and optimization design. First of all, starting with the general structure of high voltage diodes and using Silvaco-TCAD simulation software, the electric field distribution in the case of reverse breakdown is simulated and theoretically analyzed. The high voltage avalanche diode works in avalanche breakdown mode. With the increase of avalanche breakdown current, the form of electric field distribution changes. When the avalanche breakdown current increases to a certain value, the secondary electric field peak appears at the cathode side nn junction. This is the main cause of double avalanche effect and device damage. By introducing buffer layer structure between n- and n-region, the occurrence of secondary electric field spike at n _ n junction can be restrained and the breakdown tolerance of avalanche can be improved. Finally, the diode with buffer layer is optimized according to the design index. First, the blocking parameters of the non-perforated structure and the perforated structure were designed. The parameters of the diode base region of the non-perforated structure and the through-through structure with the voltage of 2300V were as follows: the doping concentration of the non-perforated structure region was 6.1 脳 1013cm-3, and the width of the base region was 280 渭 m. The doping concentration of the penetrating structure is 1.87 脳 1013cm-3 and the thickness of the base region is 160 渭 m. In this paper, the avalanche breakdown tolerance is analyzed firstly. From the viewpoint of avalanche breakdown tolerance, the non-through-through structure is more favorable to the improvement of avalanche tolerance, but the importance of conducting pressure drop in high voltage field is considered. The design of high voltage avalanche diode is carried out by adding a buffer layer to the through structure. The thickness and concentration of the buffer layer are optimized by equalizing the on-voltage drop and the avalanche breakdown tolerance. The parameters of buffer layer are as follows: buffer layer thickness is 15 渭 m, buffer layer concentration is 3 脳 1014cm-3, and buffer layer concentration is 3 脳 1014cm-3. Through the simulation analysis of high voltage avalanche diode with buffer layer structure, it is concluded that the buffer layer can effectively reduce the peak of electric field on the cathode side, delay the emergence of negative differential resistance, and improve the avalanche breakdown tolerance.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN312.7

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