New Diode-Triggered Silicon-Controlled Rectifier for Robust Electrostatic Discharge Protection at High Temperatures

The diode-triggered silicon-controlled rectifier (DTSCR) is an important device for the electrostatic discharge (ESD) protection of low-voltage integrated circuits, and its trigger voltage is determined by the forward turn-on voltage of diode string and the voltage drops on the parasitic resistors of metal interconnects. For the conventional DTSCR, the voltage drops on the parasitic resistors are often negligible so its triggering voltage is mainly determined by the forward turn-on voltage of diode string, which decreases with increasing temperature due to the inherited negative temperature coefficient. In this paper, an improved and novel device called thermal-stable DTSCR (TSDTSCR) is proposed to offer an improved ESD protection stability at elevated temperatures. This is done by changing and optimizing the 3-D layout. In particular, the experimental results show that the trigger voltage drop of the TSDTSCR can be reduced to 13.5% at 125 °C, comparing to 27.18% of the DTSCR. The holding voltage of the TSDTSCR is also more stable than that of the DTSCR over a wide range of temperatures.