Design Of 600V Super Junction VDMOS Device

Super junction is a structure combines with p-type and n-type semiconductor.The p-region and n-region close to each other,so they can be depleted by each other.Then there is very little carrier in the whole region,so it could be saw as a pure semiconductor,especially when it is used in high voltage environment.Since super junction show up,the relationship of conventional drift region's Ron,sp(?)BV5.2 have been broken down.It means higher voltage,super junction has smaller resistance.This paper based on super junction theory,design a 600 V VDMOS which possesses high break down voltage and smaller specific on resistance.The specific work of this study is as follows:(1)Two kinds of super junction cell structures have been analyzed.First establish the calculation model,then solve the point electric field,finally calculate the relationship of break-down voltage and specific on resistance.(2)Simulation and optimization of super junction cells to reduce the specific on resistance to 2.32?·Wmm,at concentration tolerance at 10%.At the same time,we found,when doping increase,the BV increase,but the Ron,sp increase too.When p-region and n-region count about half area,the BV maximum.The Ron,sp increase,with the increase of the internal radius.The maximum of BV is not obtained when the charge is completely balanced,but when it has a slight deviation.(3)A variable spacing super junction termination structure with JTE has been proposed,to solve the problem of the breakdown caused by the non-equilibrium of the edge charge,and effectively reduce the influence of the terminal surface,to make breakdown occurs mainly in the cell region.The simulation optimization of the terminal structure had been executed.The terminal break down voltage up to 722 V,terminal width of only 70 ?m.