Impacts of Embedded SCR/Schottky Parasitic on ESD Reliability in the Drain End of High Voltage nLDMOS Devices

SCR and Schottky parasitic diodes at the Drain side of nLDMOS devices were embedded to enhance the ESD discharge-current-capability and robust to the Latch-up effect of the devices. The area ratio adjustments of parasitic SCR and Schottky, It2 effectively increased the current to 9 A with a fully parasitic SCR. However, the positive feedback of the SCR resulted in a large drop in the holding voltage, which caused a Latch-up risk in the device. Compared to the nLDMOS reference device with fully parasitic SCR, the addition of both Schottky diode and SCR maintained the holding voltage at 24.13 V and with good discharge current characteristics.