Study On The Performance Of Embedded Type Dual Directional SCR Electrostatic Protective Devices

With the development of semiconductor technology,electrostatic discharge(ESD)causes the failure of integrated circuit(IC)chips and electronic products more and more serious.At present,ESD protection for electronic products and integrated circuit chips has become one of the main problems faced by product engineers.The threat of ESD to chips is more and more serious,and the research on its physical mechanism is paid more and more attention.This paper analyzes the working principle and conduction uniformity of traditional dual-direction silicon controlled rectifier(DDSCR)devices and traditional embedded DDSCR devices.Three novel embedded devices are proposed to solve the problems of poor continuity uniformity and decrease of holding voltage with the number of finger increase.The proposed device is fabricated in 0.5?m process and tested for transmission line pulse(TLP).The detailed research content is as follows:(1)The working mechanism and electrostatic performance of traditional interdigitated DDSCR devices are studied.The device simulation analysis and TLP test shows that the 1-finger DDSCR has uniform conduction in the finger width direction,and it's failure current basically increases in proportion with the increase of finger width.The forward failure current of the 40?m/80?m finger width DDSCR is3.28A and 6.30A,respectively.The non-uniform conduction phenomenon of multi-finger device is significant,and the holding voltage decreases with the increase of finger number,the failure current of the 1-,2-,and 4-finger of the traditional DDSCR is 6.22A,11.83A and 13.33A,and the holding voltage of 1-,2-,and 4-finger traditional DDSCR is 10.42V,6.67V,and 5.52V,respectively.Traditional DDSCR have the problem that the holding voltage decreases with the increase of the number of fingers.(2)Traditional embedded devices have the advantage of maintaining the voltage without exponential changes,but the problem of non-uniform conduction is serious.In response to this problem,this paper proposes two novel embedded devices MDDSCR?NE and MDDSCR?NP.The embedded fingers of the new device are turned on layer by layer from inside to outside.The holding voltage is determined by the SCR path of the innermost finger.At the same time,because the P+of the inner embedded finger is removed,the current distribution of the new device is more uniform.The TLP test results shows that the failure current of the traditional interdigital device,the traditional embedded device,MDDSCR?NP and MDDSCR?NE are 13.07A,6.81A,11.69A and 10.77A respectively,and the holding voltage is 7.63V,10.60V,14.56V and 13.14V respectively.Both new embedded devices have higher failure currents than MDDSCR devices and higher holding voltages than traditional interdigitated devices.The paper also discussed the key dimensions and indexes of the device.(3)A new embedded device MDDSCR?PW with a smaller area is proposed.The influence of the device's key size and the number of fingers on the device performance is analyzed,and constructs a MDDSCR?FPW device based on the structure of MDDSCR?PW device,which is a combination of interdigital and embedded,which provides a scheme for further improving the protection level of the device.The TLP test results show that the current leakage capacity per unit area of the MDDSCR?PW1 device,MDDSCR?NP1 device,MDDSCR?NE1 device,and DDSCR?2F device are 2.19m A/?m~2,1.69m A/?m~2,1.56m A/?m~2,and 1.83m A/?m~2respectively,and the MDDSCR?PW have the highest discharge efficiency per unit area.