多晶硅栅对LDMOS-SCR器件ESD防护性能的影响

Effect of poly-silicon gate on ESD protection performance of LDMOS-SCR devices

为了研究多晶硅栅对内嵌可控硅(SCR)的横向扩散金属氧化物半导体(LDMOS-SCR)器件静电放电(ESD)防护性能的影响,基于0.35μm Bipolar-CMOS-DMOS(BCD)工艺制备了LDMOS-SCR与SCR器件,并利用传输线脉冲测试比较它们的ESD特性.通过仿真2种器件在不同强度ESD应力下的电流密度分布,比较器件内部触发电流泄放路径的开启顺序;通过仿真2种器件在强电压回滞下的电流线和晶格温度的分布,分析因电场影响电流泄放的方式以及温度的分布而导致ESD鲁棒性的差异.仿真和测试结果表明,与SCR相比,具有多晶硅栅的LDMOS-SCR有多条导通路径且开启速度快,有更均匀的电流和电场分布;触发电压降低了12.5%,失效电流提高了27.0%,ESD鲁棒性强.

To study the effect of poly-silicon gate on the electrostatic discharge （ESD） protection performance of laterally diffusion metal-oxide-semiconductor （LDMOS） devices with embedded silicon controlled rectifier （SCR）, we prepared SCR and LDMOS-SCR devices in a 0.35 ~m Bipolar-CMOS-DMOS （BCD） process and measured their ESD characteristics by using transmission line pulse test system. We compared their turn-on sequence of trigger current discharge paths by simulated internal current density distribution at different ESD pulse. By simulating their current line and lattice temperature distributions in the turn-on state, we also compared their ESD robustness resulting from the different electric field induced current discharge methods and the temperature distribution. Both simulation and test results show that, compared with SCR, the LDMOS-SCR with poly-silicon gate has more conduction paths and more uniform current and electric field distributions, turns on faster, has a trigger voltage decreased by 12.5% and a failure current increased by 27. 0%, and exhibits the stronger ESD robustness.