An overview on the electrostatic discharge (ESD) protection circuits by using the silicon controlled rectifier (SCR)-based devices in CMOS ICs is presented The history and evolution of SCR device used for on-chip ESD protection is introduced Moreover, two practical problems (higher switching voltage and transient-induced latchup issue) limiting the use of SCR-based devices in on-chip ESD protection are reported Some modified device structures and trigger-assist circuit techniques to reduce the switching voltage of SCR-based devices are discussed The solutions to overcome latchup issue in the SCR-based devices are also discussed to safely apply the SCR-based devices for on-chip ESD protection in CMOS IC products

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Overview of on-chip electrostatic discharge protection design with SCR-based devices in CMOS integrated circuits

A novel diode-triggered SCR (DTSCR) ESD protection element is introduced for low-voltage application (signal, supply voltage /spl les/18 V) and extremely narrow ESD design margins Trigger voltage engineering in conjunction with fast and efficient SCR voltage clamping is applied for the protection of ultra-sensitive circuit nodes, such as SiGe HBT bases (eg f/sub Tmax/=45 GHz in BiCMOS-035 /spl mu/m LNA input) and thin gate-oxides (eg tox=17 nm in CMOS-009 /spl mu/m input) SCR integration is possible based on CMOS devices or can alternatively be formed by high-speed SiGe HBTs

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Diode-triggered SCR (DTSCR) for RF-ESD protection of BiCMOS SiGe HBTs and CMOS ultra-thin gate oxides

High holding current SCRs (HHI-SCR) for ESD protection and latch-up immune IC operation

A novel diode-triggered silicon-controlled rectifier (DTSCR) (Mergens et al., 2003) electrostatic discharge (ESD) protection element is introduced for low-voltage application (signal and supply voltages /spl les/ 1.8 V) with extremely narrow ESD design margins. Trigger-voltage engineering in conjunction with fast and efficient SCR voltage clamping is applied for the protection of ultrasensitive circuit nodes, such as SiGe heterojunction bipolar transistor (HBT) base regions (e.g., f/sub Tmax/=45 GHz in BiCMOS 0.35-/spl mu/m LNA input) and thin gate oxides (e.g., t/sub ox/=1.7 nm in CMOS 0.09-/spl mu/m high-speed input). Ultrathin gate protection requires a reinforced trigger diode chain to avoid SCR trigger-speed issues resulting in critical trigger-voltage overshoots for very fast ESD transients such as a charged device model (CDM). SCR integration can be realized based on parasitic n-p-n/p-n-p inherent to CMOS devices or can alternatively be implemented based on vertical high-speed SiGe HBT with adjacent p+ SCR anode.

Speed optimized diode-triggered SCR (DTSCR) for RF ESD protection of ultra-sensitive IC nodes in advanced technologies

This paper presents a novel SCR for power line and local I/O ESD protection. The HHI-SCR exhibits a dual ESD clamp characteristic: low-current high-voltage clamping and high-current low-voltage clamping. These operation modes enable latch-up immune normal operation as well as superior full chip ESD protection. The minimum latch current is controlled by device design. The HHI-SCR is demonstrated in 0.10um-CMOS and in a 0.4um-BiCMOS technology. The design is highly area efficient.

Mergens

Papers

GGSCRs: GGNMOS Triggered silicon controlled rectifiers for ESD protection in deep sub-micron CMOS processes