NLDMOS device and manufacture method thereof

Abstract

The invention discloses an N-type Laterally Diffused Metal Oxide Semiconductor (NLDMOS) device including the following steps that: a field oxide is formed above a drift region, a second side of the drift region field oxide is in lateral contact with a drain region; a first side of the drift region field oxide is arranged at the bottom of a polycrystalline silicon gate, and the first side of the drift region field oxide and a P well are separated by a distance; part of the field oxide at a top region of the first side of the drift region field oxide is removed, and the region where the field oxide is removed is filled with a substitute dielectric layer which has a character that the capacity for blocking ion implantation of the substitute dielectric layer is larger than that of the field oxide or a relative dielectric constant of the substitute dielectric layer is larger than that of the field oxide; and by using the character of the large capacity for blocking the ion implantation, the substitute dielectric layer makes a doping concentration of the drift region at the bottom of the first side of the drift region field oxide lower, thereby improving a breakdown voltage of the NLDMOS device, and by using the character of the large relative dielectric constant, the substitute dielectric layer makes the electric field strength at the bottom of the first side of the drift region field oxide reduce, thereby improving the breakdown voltage of the NLDMOS device. The invention also discloses a manufacture method of the NLDMOS device.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to an N-type laterally diffused metal oxide semiconductor (NLDMOS) device; the invention also relates to a manufacturing method of the NLDMOS device. Background technique [0002] In LDMOS devices, on-resistance is an important indicator. In order to make high-performance LDMOS, it is usually necessary to add an additional N-type implant in the drift region of the device to make the device have a lower on-resistance, and this method will reduce the breakdown voltage of the device. For process platforms with a size below 180nm, the isolation structure of LDMOS is shallow trench field oxygen (STI) isolation. When breakdown occurs, the corner of STI is the strongest point of impact ionization, where the electric field intensity is the highest. In order to improve the breakdown voltage of the device , it is necessary to reduce the doping concentration in th...

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Problems solved by technology

In order to make high-performance LDMOS, it is usually necessary to add an additional N-type implant in the drift region of the device to make the device have a lower on-resistance, and this method will reduce the breakdown voltage of the device

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