Laterally diffused metal oxide semiconductor device and manufacturing method thereof

Abstract

The invention relates to a laterally diffused metal oxide semiconductor device comprising a shallow trench isolation structure and a polycrystalline silicon gate electrode. The polycrystalline silicon gate electrode partially covers the shallow trench isolation structure. The shallow trench isolation structure is provided with a groove. The device also comprises an extension part which is directly connected with the polycrystalline silicon gate electrode and fills in the groove. Material of the extension part is semiconductor material or metal material. The invention also relates to a manufacturing method of the laterally diffused metal oxide semiconductor device. The polycrystalline silicon gate electrode covering the STI extends into the groove of the STI, and effective distance to a drift region silicon is reduced and capacitance is increased. Influence of charges on Idlin is weakened due to the effect of gate voltage even the charges are captured at the corner of the STI so that Idlin degeneration is reduced and the HCL service life of the device is enhanced. When the device is in the off-state, drift region exhausting can be enhanced by the extension part, and accumulation of N-type impurities in the region beside the STI and the region covered below the polycrystalline silicon can be enhanced by gate voltage in the on-state so that off-BV can be enhanced and Rdson can be reduced.

Description

technical field [0001] The present invention relates to a semiconductor device, in particular to an LDMOS device, and also to a manufacturing method of the LDMOS device. Background technique [0002] As laterally diffused metal oxide semiconductor (LDMOS) devices are more and more widely used in integrated circuits, there is an increasing demand for LDMOS with higher off-state breakdown voltage (off-BV) and smaller on-resistance (Rdson) more urgent. The smaller the Rdson, the higher the concentration of the drift region, the larger the electric field of the LDMOS during operation, the more serious the hot carrier injection (HCI) phenomenon, and the worse the device life. Especially for LDMOS with a shallow trench isolation (STI) structure in the drift region, since the current will flow directly through the corner of the STI when it is in the on state, strong impact ionization is generated here, so that hot carriers are injected into the STI edge corners, resulting in devi...

AI Technical Summary

Problems solved by technology

[0005] Based on this, it is necessary to provide a laterally diffused metal oxide semiconductor device that can not only solve the problem of hot carrier injection, but also take into account off-BV and Rdson

Images