Esd implantation method in deep-submicron cmos technology for high-voltage-tolerant applications with light-doping concentrations

Abstract

An implanting method forms high-voltage-tolerant ESD protection devices (ESDPD) for deep-submicron CMOS process activated between LDD implanting and forming sidewall spacers. ESD-Implant (ESDI) regions are located at the ESDPD, without covering the center region under the drain contact (DC). The ESDI LDD concentration and doping profile are deep to contain drain diffusion. Regions with the ESDI have a high junction breakdown voltage (JBV) and a low junction capacitance. After forming gate sidewall spacers, implant high doping concentration ions into active D/S regions forming a shallower doping profile of the D/S diffusion. The drain has a JBV as without this ESDI, so the ESD current (ESDC) is discharged through the center junction region under the DC to bulk, far from the ESDPD surface channel region. The ESDPD sustains a high ESD level. The original drain JBV of an MOS with this ESDI method is unchanged, i.e. the same as that having no such ESDI, so it can be used in I/O circuits with high-voltage signals in the deep-submicron CMOS. The ESD level of the I/O ESDPD improves. This method applies to high-voltage-tolerant I/O pins in a deep-submicron CMOS. The ESD discharge current path in the MOS device structure improves the ESD level in the output buffer MOS. ESDI regions are located at the output MOS devices, without covering the region under the DC. The method has a LDD concentration, so regions with this ESDI have a higher JBV and a lower junction capacitance. Regions under the DC without this ESDI have an unchanged JBV, so the ESDC discharges through the junction region under the DC to bulk.