摘要
瞬态电压抑制器(Transient Voltage Suppressor,TVS)作为常用的防护型器件具有吸收功率高、响应速度快等特点。目前,雪崩型SiC-TVS器件尚缺乏合理的终端设计,以常用N型衬底为基础的外延P+N-N+/Mesa结构SiC-TVS器件在反偏P+/N-结边缘处易形成负斜角边缘结构,导致器件因边缘电场集中而提前击穿,严重影响器件的工作可靠性。本文基于Sentaurus TCAD数值仿真,研究了一种雪崩型SiC-TVS器件结构,该结构采用离子注入形成大曲率半径的U型平面PN结,并将其边缘与Mesa沟槽终端顶点在器件上表面以距离x进行耦合设计,使器件表面形成正斜角终端,有效地避免了边缘电场集中效应。同时x的选取具有一定余量,在工艺上较易实现。最后利用该结构仿真得到了响应时间约5.3ns、钳位因子达到1.01的雪崩型SiC-TVS器件,仿真结果表明新型耦合结构器件对异常瞬态浪涌信号表现出良好的抑制效果。
Transient Voltage Suppressor(TVS)is characterized by high power absorption and fast response,which is commonly used as protective device.However,conventional avalanche-type SiC-TVS with an epitaxial PN base and mesa-termination has usually suffered from electric field crowding taking place at the the negative bevel mesa near the p-n junction,resulting in a potentially premature breakdown for the device.In this paper,an improved SiC-TVS structure with mesa coupled with U-shaped implanted PN junction is proposed and investigated using numerical simulation.By optimizing the key parameters such asθ1 and x,i.e.,mesa inclined angle and coupled distance between the U-shaped junction edge and mesa vertex respectively,a positive bevel mesa effect with a certain process tolerance could be achieved,thus effectively promoting the breakdown and clamping reliability.A response time of 5.3ns and a clamping factor of 1.01 are obtained from the same improved avalanche-type SiC-TVS respectively,which shows a good suppression effect on abnormal transient surge signals.
作者
韩超
HAN Chao(Xidian-Wuhu Research Institute)
出处
《中国集成电路》
2023年第6期51-57,共7页
China lntegrated Circuit
