A Dual-Direction SCR Featuring Shallow Snapback and High-Temperature Robustness for ESD Protection of Industrial Communication Buses

Abstract

The reliability standards for on-chip electrostatic discharge (ESD) protection in high-voltage industrial communication buses are stringent, and traditional ESD solutions cannot effectively meet the requirements for high holding voltage ( Vh ) and high-temperature tolerance in these applications. Therefore, this article presents a dual-direction silicon-controlled rectifier (DDSCR) featuring shallow snapback and high-temperature robustness. At the same size, Vh (38.4 V) of the parallel NPN-enhanced SCR (NPNE_DDSCR), which employs a metal short and no shallow trench isolation (STI), is significantly higher than that of the traditional structure (T_DDSCR) and the parallel NPN structure (NPN_DDSCR). Under high-temperature conditions ranging from 50 ∘ C to 125 ∘ C, the structure maintains nanoampere-level leakage current, and the device’s ESD characteristics show no significant degradation. The electrostatic properties of three types of structures were verified based on the 0.18- μ m bipolar-CMOS–DMOS (BCD) process, and their operating mechanisms were further analyzed using technology computer-aided design (TCAD) simulations. The results show that the NPNE_DDSCR exhibits superior performance, with a human body model (HBM) level exceeding 8 kV, and is suitable for efficient on-chip ESD protection of industrial communication buses.

Bingjun Xiong

PhD Student

My research interests include circuit design of optical receivers and references.

Jingjing Liu

Associate Professor

My research interests include low-power smart micro-sensor integrated circuit design, image sensors, biomedical sensors, and energy harvesting circuits.