基于3D仿真的LDMOS-SCR器件优化

Optimization of LDMOS-SCR Device Based on 3D Simulation

为了提高内嵌可控硅(SCR)的横向扩散金属氧化物半导体(LDMOS-SCR)器件应用于高压时的ESD防护性能,基于0.35μm BCD工艺,在典型LDMOS-SCR(Dut1)基础上,制备了两种实验器件,即阳极环N+区的LDMOS-SCR(Dut2)和在阳极端引入漂移层的LDMOS-SCR(Dut3)。在ESD应力作用下,器件开启后的3DTCAD仿真结果表明,相比于Dut1,Dut2和Dut3的电流密度更小,Dut2和Dut3的导通电阻更大。传输线脉冲的测试结果表明,器件的维持电压分别从2.74V增至8.41V和16.20V,Dut2、Dut3的品质因数较Dut1分别增大了1.96倍、3.52倍。该3DTCAD仿真及版图改进方法可为高压IC的ESD防护设计提供有益参考。

In order to improve the electrostatic discharge（ESD）protection performance of silicon controlled rectifier embedded lateral diffused metal oxide semiconductor（LDMOS-SCR）devices at high voltage,based on typical LDMOS-SCR（Dut1）,two types of experimental devices including LDMOS-SCR with an N＋ type ring at the anode region（Dut2）and LDMOS-SCR with a drift layer at the anode region（Dut3）were fabricated in a 0.35μm bipolar-CMOS-DMOS process.The 3D TCAD simulation results of the turned-on devices under the ESD stress indicated that the Dut2 and Dut3 devices had a smaller current density and a larger on-resistance than the Dut1 device.The transmission line pulse test results of these devices also showed that the holding voltage increased from 2.74 V to 8.41 Vand 16.20 V,and the quality factor of Dut2 and Dut3 increased by about 1.96 and 3.52 times respectively.The methods of 3D TCAD simulation and layout optimizations of experimental devices used in this work could provide a useful reference for designing ESD protection devices in high voltage IC.