An Ultra-Low Specific On-Resistance VDMOS with a Step Oxide-Bypassed Trench Structure
具有超低导通电阻阶梯槽型氧化边VDMOS新结构

A novel Step Oxide-Bypassed (SOB) trench VDMOS structure is designed based on the Oxide-Bypassed concept proposed by Liang Y C.This structure is suitable for breakdown voltage below 300V to obtain ultra-low specific on-resistance.The main feature of this structure is the various thicknesses of sidewall oxide,which modulate electric field distribution in the drift region and the charge compensation effect.As a result,the breakdown voltage is increased no less than 20% due to the more uniform electric field of the drift region,while the specific on-resistance was reduced by 40%~60% for the step oxide bypassed compared with the oxide-bypassed structure.