ESD Capability Analysis of High-voltage nLDMOSs by the Bulk Terminal Modulation

Due to the low barrier of the Schottky contact surface, the application of Schottky at the bulk side of octagon-type nLDMOS is studied in this paper. The electrostatic discharge (ESD) protection devices in this work are the N-channel Lateral Diffused Metal Oxide Semiconductor (nLDMOS) structure, which is fabricated using a TSMC 0.18µm high voltage (HV) process. The bulk terminal is divided into two parts: the outer zone and the inner zone. Schottky diodes are parasitized at different locations of the bulk terminals, and three sample groups are designed. These components are tested by a TLP tester. Since the equivalent Schottky devices are parasitized in the forward direction at the bulk terminal, this makes the parasitic BJT conduct better. As a result, the triggering voltage (V
t1
) and holding voltages (V
h
) are reduced. The capability shows that the secondary breakdown current (It2) can be increased up to 5.38 A.