LDMOS and manufacturing method thereof

Abstract

The present invention relates to a LDMOS (Lateral Double-diffused metal oxide semiconductor) and a manufacturing method thereof. A first buried layer with an impurity total amount gradually decreasedfrom left to right is injected and formed on a substrate, in the later diffusion process, the left side of the first buried layer is diffused towards the upper portion of an epitaxial layer due to theimpurities, the effective junction depth of the left side of the epitaxial layer becomes shallow, N-type impurities are decreased, when reverse bias is applied between the source and the drain of theLDMOS, the epitaxial layer region at the left side is easily exhausted, the exhaust line in the epitaxial layer region is rapidly extended towards the right with the increasing of the reversed bias voltage so as to have an effect on reduction of a peak electric field of the region, the junction depth of the region at right side of the first buried layer becomes shallow, P-type impurities are gradually decreased, the exhaust line of the P-type region can be rapidly extended towards a substrate region with a relative light concentration so as to rapidly reduce the electric field intensity of the drift region, improve the voltage endurance capability of the drift region and allow the device not to be untimely broken down in a vertical direction.

Description

technical field [0001] The invention belongs to the field of semiconductor manufacturing, and in particular relates to an LDMOS and a manufacturing method thereof. Background technique [0002] Lateral Double-diffused metal oxide semiconductor (LDMOS) is a high-voltage power device, which has the characteristics of high operating voltage, relatively simple process, and high switching frequency, and the processing technology based on bulk silicon materials is relatively mature. Therefore, LDMOS devices have broad development prospects. The drain, source and gate of the LDMOS device are all located on its surface, which is easy to integrate into the chip, so it is especially suitable as a high-voltage power device in high-voltage integrated circuits and power integrated circuits. [0003] In order to increase the breakdown voltage of LDMOS, a drift region is usually added between the source region and the drain region. When a reverse bias is applied between the source and dra...

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Problems solved by technology

[0003] In order to increase the breakdown voltage of LDMOS, a drift region is usually added between the source region and the drain region. When a reverse bias is applied between the source and drain, the drift region will form a depletion layer, and the depletion layer has two depletion layers. The distance between two depletion lines determines the e

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