A Novel SCR-based Schottky Diode and Lightly P-well Additions of HV 60V nLDMOS on ESD Capability

Abstract

Using an embedded silicon-controlled rectifier (SCR) on the protection element was often used in the high-voltage electrostatic discharge (ESD) protection design. In this paper, a novel structure of embedded SCR on HV n-channel lateral diffused MOS (nLDMOS) is proposed, which has a higher secondary break current (It2) than the original structure of embedded SCR by embedding an SCR in the drain middle zone, and it can significantly improve the risk of the too low holding voltage. In addition, by the drain-side heavily doped (N+) removed equivalent a Schottky diode addition, which is helpful for improving the discharge current capability. Moreover, adding the lightly P-type well below the P+ region of the embedded SCR can more improve the capability of discharge ESD current. The elements after adjustment, the proposed embedded SCR element can have higher Latch-up immunity and greatly improve the ESD immunity of the protection elements.