An Improved Bidirectional SCR Structure for Low-Triggering ESD Protection Applications

An improved dual-polarity silicon-controlled rectifier (SCR) device has been proposed and realized in a 0.6-mum bipolar complementary metal-oxide-semiconductor process. The device can be used to protect electrostatic discharge (ESD) in both the positive and negative directions on pins with a voltage range that goes below ground. Comparing with the conventional bidirectional SCR structures, the new device is more suitable for low-voltage integrated circuit ESD protection applications because it possesses a smaller trigger voltage, a smaller leakage current, and a larger holding voltage.