Study On Structure Design And Performance Of SCR Electrostatic Protection Device With High Voltage Process

With the progress and development of science and technology,automobile electronics,smart phones,ultra-thin notebook computers,smart wearables and smart home have penetrated into all aspects of people's lives,which also makes the application of electrostatic protection devices of high voltage technology more extensive.However,due to the development of the process and the smaller and smaller size,electrostatic protective devices will be affected by different degrees of Electrostatic Discharge(ESD)in the process of transportation,testing and use.Therefore,the research of electrostatic protective devices has been paid more and more attention.This paper is based on 0.18?m Bipolar CMOS DMOS(BCD)technology,In this paper,the structures and operating principles of conventional Silicon Controlled Rectifier(SCR),conventional High Voltage symmetric Dual Direction SCR(HVDDSCR)and High Voltage Asymmetric Dual Direction SCR with DWELL(ADDSCR?DW)are studied and analyzed,the performance of the above devices are optimized to obtain better ESD performance.The new devices are simulated and tested by using a TCAD simulation and a transmission line pulse(TLP)system.The specific research contents are as follows:(1)The structure,working principle and latch mechanism of traditional SCR devices are discussed.In order to solve the problem of low holding voltage of SCR devices,two solutions are proposed in this paper: The first is to change the key dimension of the device D16.Increasing D16 can reduce the emitter current gain ? of the parasitic NPN transistor,and then increase the holding voltage of the device;The second is to propose a SCR device with a silicide barrier layer(salicide-blocking,SAB).The addition of the SAB layer increases the ballast resistance on the SCR path,thus the holding voltage is increased from 3.03 V to 15.03 V.(2)The structure and working principle of traditional high voltage symmetric HVDDSCR are discussed,the effects of different key dimensions and different number of fingers on device performance are analyzed: The influence of key dimensions of D14 and D9 on the holding voltage of HVDDSCR devices is investigated.The holding voltage of HVDDSCR devices could be increased by increasing D14 or decreasing D9.When D14=H+1?m,the holding voltage is increased from 25.3V to 30.4V,when D9=I?m,the holding voltage is increased from25.9V to 29.5V.The influence of different number of fingers on the holding voltage and failure current of HVDDSCR device is investigated.(3)The structure and working principle of high voltage asymmetric ADDSCR?DW with deep well(DW)are studied,the factors affecting the trigger voltage,the influence of different number of fingers on device performance and the optimization of key dimension D12 are analyzed: The factors that affect the trigger voltage of ADDSCR?DW are explored.The influence of different number of fingers on the holding voltage and failure current of ADDSCR?DW device is investigated.The influence of key dimension D12 on the holding voltage of ADDSCR?DW device is investigated,when D12=L+1.5?m,the holding voltage is increased from 26.9V to33.4V.