PF-CSTBT结构特性的优化设计

Optimal design structure and characteristics of PF-CSTBT

针对PF-CSTBT结构中,CS层与P浮层对导通压降与击穿电压的影响有着矛盾关系这一问题,本文通过运用Silvaco TCAD软件的Athena及Atlas,保证CS层中离子注入的掺杂总量一定,采用高斯分布与线性和均匀分布,在击穿电压几乎不变的情况下,其导通压降分别下降15.3%与8%。针对CSTBT结构中,沟槽栅底部倒角处,电场分布集中,易击穿这一问题,本文亦从CS层的载流子浓度大小、P浮层的掺杂峰值浓度位置,P浮层PN结深等方面,降低导通压降,并提高击穿电压。仿真结果表明,在PF-CSTBT结构中,CS层高斯分布是最佳分布形式;增加CS层高斯分布峰值浓度可以有效降低导通压降;P浮层高斯掺杂浓度峰值位置的选择在11μm时,在导通压降不变的情况下,正向击穿电压提高3%。

In the PF-CSTBT structure,there is a contradictory relationship between the CS layer and the P floating layer on the effect of the conduction voltage drop and the breakdown voltage.By Athena and Atlas of Silvaco TCAD software,ensuring the total amount of dopant in the CS layer,the Gaussian distribution,uniform and linear,the conduction voltage drop decreases by 15.3%and 8%,when the breakdown voltage is almost constant.In the CSTBT structure,the chamfer at the bottom of the trench gate,the electric field distribution is concentrated,easy breakdown,It is also from the carrier concentration of CS layer,the doping peak concentration position of P-floating layer and PN Junction depth of P-floating layer to ensure the same voltage drop,and improve the breakdown voltage.The simulation results show that Gaussian distribution of CS layer is the best distribution,with the peak concentration of the gaussian distribution in the CS layer decreased,the on-state voltage drop can be effectively reduced.When the Gaussian doping concentration peak position of P-floating is selected at 11μm,the forward breakdown voltage increases by 3%.