A New Dual-Direction SCR With High Holding Voltage and Low Dynamic Resistance for 5 V Application

Abstract

Dual-directional silicon-controlled rectifiers (DDSCRs), which provide both positive and negative electrostatic discharge (ESD) surge paths, are ESD protection devices with an excellent area efficiency. However, DDSCRs have a low holding voltage for use in 5 V-class applications, with a relatively high on-state resistance because of the elongated ESD surge path compared to unidirectional SCRs. In this paper, we propose a novel DDSCR with a higher holding voltage and a better ESD tolerance than conventional low-triggering DDSCRs (LTDDSCRs), realized by operating two additional parasitic bipolar transistors. The proposed ESD protection device was developed through a 0.18- $\mu \text{m}$ CMOS process, and a timeline pulse system was used to verify its properties. The measurement results show that the proposed ESD protection device exhibits an improved tolerance and a high holding voltage and is expected to be reliable in 5 V-class applications