双阈值场板栅实现快速IGBT的机理研究

Due to the conductivity modulation effect, IGBT possesses low on-state voltage drop but slow turnoff. By conventional anode gate, the excess-carrier extraction path turned on in IGBT’s off-state cannot be turned off in IGBT’s on-state, and vice versa. To enhance the on-state/switching-speed tradeoff and solve the problem in conventional anode gate, we propose a new anode gate concept, dual-threshold field-plate gate (DTFPG) that controls the on and off of the excess-carrier extraction path, and will study the physics therein. In IGBT’s off-state, the on-threshold of the DTFPG, VT-ON, different from IGBT’s threshold VT, is so low that a low resistance extraction path will easily be formed. In IGBT’s on-state, the off-threshold of the DTFPG, VT-OFF, is so high that no extraction path will be formed, without any effect on the hole injection from anode and thus on the conductivity modulation. We will focus on the physics in DTFPG turning on and off of the excess-carrier extraction path, find the ranges of VT-OFF and VT-ON respectively in IGBT’s on-state and off-state, quantitatively evaluation the turn-off improvement of IGBT with DTFPG, and finally explore different approaches for the field plate gate to get dual threshold from material physics, structures, and electronics.

电导调制效应降低绝缘栅双极晶体管(IGBT)导通压降的同时延长了关断时间。为突破IGBT导通压降和关断时间的约束关系，解决常规内置辅助栅很难同时满足IGBT开启时关断少子抽出通道、关断时开启少子抽出通道的问题，本项目提出一种双阈值场板辅助栅，研究其控制IGBT少子抽出通道开关的物理机制。在IGBT关断时，双阈值场板栅开启电压(VT-ON，区别于IGBT主控栅的阈值电压VT)很低，很容易开启一条低阻的非平衡电子抽出通道；在IGBT开启时，双阈值场板栅关断电压(VT-OFF)很高，可完全关断非平衡电子的抽出通道，不影响阳极空穴注入和导通压降。本项目研究双阈值场板栅IGBT的开启与关断机制，探索满足IGBT正常开启与快速关断的双阈值场板栅的VT-OFF与VT-ON取值范围，量化分析双阈值场板栅对IGBT开关速度的改善程度，最后从材料、结构和器件出发，研究场板栅双阈值的实现方案。

电导调制效应降低绝缘栅双极晶体管(IGBT)导通压降的同时延长了关断时间。为突破IGBT.导通压降和关断时间的约束关系，解决常规内置辅助栅很难同时满足IGBT开启时关断少子抽出.通道、关断时开启少子抽出通道的问题，本项目提出一种双阈值场板辅助栅，研究其控制IGBT.少子抽出通道开关的物理机制。在IGBT关断时，双阈值场板栅开启电压(VT-ON，区别于IGBT主.控栅的阈值电压VT)很低，很容易开启一条低阻的非平衡电子抽出通道；在IGBT开启时，双阈.值场板栅关断电压(VT-OFF)很高，可完全关断非平衡电子的抽出通道，不影响阳极空穴注入和.导通压降。本项目研究双阈值场板栅IGBT的开启与关断机制，探索满足IGBT正常开启与快速关.断的双阈值场板栅的VT-OFF与VT-ON取值范围，量化分析双阈值场板栅对IGBT开关速度的改善.程度，最后从材料、结构和器件出发，研究场板栅双阈值的实现方案