功率MOSFET的终端耐压特性研究

发布时间：2018-04-21 23:39

本文选题：功率MOSFET + 边端设计　；参考：《西南交通大学》2015年硕士论文

【摘要】：功率半导体器件是电力电子技术发展的基础,功率MOSFET由于其具有高输入阻抗、低驱动功率、高开关速度、优越的频率特性以及良好的热稳定性等特点,自最初诞生以来,其结构和性能得到了迅速的发展。功率MOSFET的发展趋势是持续缩小芯片内单位元胞面积与边端尺寸,因为更小的面积意味着更大的沟道密度和更低的导通电阻,或者在相同的导通电阻下可以获得更小的芯片面积,进而降低成本,而更短的边端尺寸同样意味着在芯片面积不变的情况下更多的元胞容纳数目,更低的导通电阻。功率MOSFET的主要设计矛盾是保证击穿电压(Breakdown Voltage,BV)和芯片面积的前提下,尽可能的降低器件的导通电阻Rds(on),这也成为当今功率MOSFET技术发展的主要方向。本论文的主要研究内容是功率器件的耐压优化设计,首先研究功率器件本身的击穿机制；然后研究功率器件芯片的边端保护结构以及优化,这一部分包括了传统结构下场板场环的复合应用模型以及通过扩散浓度的控制而实现的横向变掺杂模型。具体研究内容如下：(1)垂直功率器件的重要参数组成,其中耐压是功率器件的关键参数之一,通过理论与仿真研究了垂直功率器件的设计与其耐压之间的相互影响。(2)普遍工艺下为了实现电场在芯片边端处的收敛,通常采用场板与场环的复合使用,文章通过场板场环设计中的关键参数研究,在较小占用芯片面积的情况下实现了高耐压。(3)为了在更短的边端长度下实现同样水平甚至更高的耐压,本文讨论了通过控制边端掺杂浓度实现的高电场强度承受能力的边端技术,通过理论与仿真讨论了该种设计下的关键参数以及实际耐压水平。
[Abstract]:Power semiconductor devices are the basis of the development of power electronics technology. Power MOSFET, because of its high input impedance, low driving power, high switching speed, superior frequency characteristics and good thermal stability, has been born since the beginning. Its structure and properties have been developed rapidly. The trend of power MOSFET is to continuously reduce the cell area and the side end size of the chip, because smaller area means greater channel density and lower on-resistance, or smaller chip area can be obtained under the same on-resistance. This in turn reduces costs, while shorter end sizes also mean more cell accommodations and lower on-resistance when the size of the chip remains the same. The main design contradiction of power MOSFET is to ensure breakdown voltage Breakdown voltage BV) and chip area, and to reduce the on-resistance of the device as much as possible, which has become the main direction of the development of power MOSFET technology. The main content of this thesis is the design of the power device. Firstly, the breakdown mechanism of the power device itself is studied, then the side protection structure and the optimization of the power device chip are studied. This part includes the composite application model of the field ring of the traditional structure and the transversely variable doping model realized by the control of diffusion concentration. The specific contents of the study are as follows: (1) the important parameters of the vertical power device, among which the voltage withstand is one of the key parameters of the power device. In order to realize the convergence of electric field at the edge end of the chip, the composite use of the field plate and the field loop is usually adopted in order to realize the convergence of the electric field at the edge of the chip under the universal process of the design of vertical power device and the interaction between its voltage and voltage. Through the research of the key parameters in the design of the field plate ring, a high voltage withstanding is realized in the case of less chip area. (3) in order to achieve the same level or higher voltage under the shorter side end length, In this paper, the edge-end technology of high electric field strength bearing capacity by controlling the edge-end doping concentration is discussed, and the key parameters and the actual voltage withstand level of the design are discussed through theory and simulation.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN386

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