A Dual-directional SCR based ESD Protection Design with High Holding Voltage using Embedded MOSFET for 12-V Applications

This study proposed a dual siliconcontrolled rectifier (SCR)-based protection device with an enhanced structure and high holding voltage for protection against electrostatic discharge (ESD). The structure facilitates an electrical connection between the bridge and additional N+ diffusion regions to turn on an additional NPN parasitic bipolar transistor on the SCR loop path and reduce the SCR positive feedback loop gain. Consequently, the snapback characteristics of the conventional device were improved. A two-dimensional technology computer-aided design (TCAD) simulation was performed to verify the operating principles and identify the characteristics of this device. Subsequently, the proposed device and a low-trigger dual-directional (LTDD) SCR were fabricated using a 0.18 μm bipolar-CMOS-DMOS (BCD) process under identical conditions. Further, the transmission-linepulse (TLP), transient latch-up (TLU) measurement method, and hot-chuck control system were used to evaluate the electrical characteristics and thermal reliability. In addition, the electrical characteristics of the device were optimized utilizing design variables. The measurement results indicated that the proposed device exhibited an improved holding voltage of 11.31 V, which was further optimized to 14.24 V using a suitable design parameter. Moreover, it demonstrated sufficient thermal reliability with a holding voltage greater than 12 V at 500 K. Therefore, this device is suitable for 12-V-class applications and is expected to provide excellent area-based efficiency and thermal reliability.