MOSFET栅下碰撞电离与击穿研究

研究了场板终端技术对改善 MOSFET栅下电场分布和碰撞电离率的作用 ,结果表明 ,MOSFET在高压应用时 ,漏极靠近表面的 PN结处电场最强 ,决定器件的击穿特性。通过对实验研究与计算机模拟结果的分析 ,表明在不同的栅压下 ,此处场板长度的大小对栅下电场强度有直接的影响 ,合理地控制场板长度能有效地提高器件的击穿电压。

The Research about Impact Ionization and Breakdown under Gate of MOSFET

The effect on improving electric field distribution and reducing ratio of impact ionization by using field plate is investigated. The results show that, in MOSFET applied under high voltage, the strongest electric field is located around the PN junction close to surface at drain, which limits breakdown voltage of MOSFET. By experimentalizing and analyzing the simulation result with computer, it can be seen that, under different gate voltages the length of the field plate affects the electric field intensity beneath gate directly. So we can reduce electric field intensity there effectively and increase breakdown voltage by controlling the field plate length reasonably.