High-reliability lateral double-diffusion metal oxide semiconductor tube

Abstract

A high-reliability lateral double-diffused metal oxide semiconductor tube, comprising: an N-type substrate, a P-type epitaxial layer is arranged on the N-type substrate, and a P-type body region and an N-type body region are arranged inside the P-type epitaxial layer. In the P-type body region, an N-type source region and a P-type body contact region are arranged, an N-type buffer layer is arranged in the N-type drift region, and an N-type drain region is arranged in the N-type buffer layer. The surface of the P-type epitaxial layer is provided with a gate oxide layer and a field oxide layer, and a polysilicon gate is provided on the surface of the gate oxide layer and extends to the upper surface of the field oxide layer. The structure that can reduce the hot carrier effect is composed of multiple The trench array formed by the trench is located in the field oxide layer region under the polysilicon gate, and the trench array is filled with polysilicon and connected with the polysilicon gate. The introduced groove array can effectively reduce the impact ionization peak at the junction of the gate oxide layer and the field oxide layer, reduce the hot carrier degradation of the device, and improve the reliability of the device.

Description

technical field [0001] The invention mainly relates to the reliability field of high-voltage power semiconductor devices, specifically a high-reliability lateral double-diffusion metal oxide semiconductor tube, which is suitable for improving the lateral double-diffusion technology prepared by using Bipolar, CMOS, and DMOS (BCD) techniques. The working life of metal oxide semiconductor tubes. Background technique [0002] With the increasing demand for energy saving, the performance of high-voltage power integrated circuit products has received more and more attention, and the reliability of devices has also attracted more and more attention from circuit design engineers. The hot carrier effect is a very important reliability problem, and it is also one of the main factors affecting the working life of the device. At present, while continuously reducing the feature size of the process, it is also required that the device can work at a higher operating voltage, so the requir...

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Problems solved by technology

However, since the thickness of the gate oxide layer of the lateral double-diffused metal oxide semiconductor transistor is usually one-tenth or even less than the thickness of the field oxide layer, the junction of the gate oxide layer and the field oxide layer is often the most serious area where the electric force lines on the surface of the device gather. The area has a higher electric field intensity, so it is easier to form hot carriers, so that the impact ionization rate of carriers in this area is very high, which is the area where the hot carrier effect is the most serious, and it is also the area that affects the degradation of device performance parameters. most important area

At present, methods such as stepped field oxide layer have been used to reduce the hot carrier effect at the junction of the gate oxide layer and the field oxide layer, but usually need to add an additional mask or implantation steps, so there is a cost in the manufacturing process. increased by

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