Design Of DMOS Device Based On Multiple Ion Implantation

Power DMOS is a kind of power electronic device developed on the basis of MOS integrated circuit technology.It has many advantages,such as high input impedance,fast switching speed and small driving power.In recent years,many domestic enterprises have mastered the production technology of power device,and the market competition is becoming increasingly fierce.Enterprises have to improve product yield,reduce production costs and shorten production time to establish itself in the fierce market competition.The threshold voltage is an important parameter of DMOS,which has important influence on the turn-on and turn-off characteristics of the device,and the doping distribution of Pbody has a significant influence on this parameter.According to the requirement of project partners,and based on in-depth analysis of the working principle,device structure and process flow of DMOS,this paper optimize the structure and manufacturing method of conventional trench DMOS.The solution is to change the "ion implantation + thermal diffusion at high temperatures " into "multiple ion implantation + RTP",in order to improve the product yield and shorten the production time.On the basis of the technological level of the project partners,the optimized design of the structure and the process of the trench gate DMOS device are carried out.In this paper,we use SILVACO to simulate the structure parameters and the process parameters of the device.The influence of the epilayer and the substrate on the breakdown voltage and conduction resistance,and the influence of the ion implantation energy and dose of Pbody on the threshold voltage and conduction resistance are systematically studied.Based on that,the optimized device structural parameters and process parameters are obtained.Finally,the device produced by foundry get the following parameters: the threshold voltage is about 1.3V~1.4V,and the yield of the threshold voltage exceeds 99%,and the Ron is less than 23 m?,and the BV is greater than 68 V,and the production time is shorten about 10 hours.