ESD (electrostatic discharge) high-voltage DMOS (diffused metal oxide semiconductor) device and manufacturing method thereof

Abstract

The invention discloses an ESD (electrostatic discharge) high-voltage DMOS (diffused metal oxide semiconductor) device which comprises an ESD ion injection region, wherein the ESD ion injection region is formed in part of a drift region under a field oxide layer, impurity ions are injected into a buried layer and enter into the drift region by annealing, propelling and diffusing, and the ESD ion injection region has impurity distribution with gradually reduced concentration between the buried layer and the bottom of the field oxide layer. The invention further discloses a manufacturing methodof the ESD high-voltage DMOS device. By adopting the device and the manufacturing method, the trigger voltage of the device can be effectively reduced, the resistance of the drift region and the on-resistance of the device can be reduced, the strength of a surface electric field of the drift region can be reduced, and a gate oxide can be protected.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to an ESD high-voltage DMOS device, and also relates to a manufacturing method of the ESD high-voltage DMOS device. Background technique [0002] In the BCD process, the design and manufacture of high-voltage ESD devices is an important part of the whole process, and it is also one of the difficulties. The main reasons are: 1. The trigger voltage of ESD high-voltage devices must be accurately designed, which cannot be higher than the breakdown of devices in the internal circuit 2. Carefully design the impurity distribution in the device, optimize the electric field distribution in the device, and try to keep the maximum electric field in the drift region away from the surface when ESD is triggered, so as to avoid damage to the gate oxide when triggered Third, reduce the on-resistance of the ESD device as much as possible, and enhance the device's ability...

AI Technical Summary

Problems solved by technology

However, by increasing the implant dose in the drift region implantation, the optimization of ESD devices cannot usually be achieved. This is because the impurities in the drift region need to go through a high-temperature advancement process. The result of increasing the implant dosage is that the surface and internal concentrations of the drift region increase after the advancement. This will increase the surface electric field in the drift region when triggered, making the gate oxide more susceptible to damage

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