High-voltage semiconductor device and manufacturing method thereof

Abstract

The invention provides a high-voltage semiconductor device and a manufacturing method thereof. The high-voltage semiconductor device comprises a substrate, first well regions, second well regions, field injection regions, source regions, drain regions, field oxidization layers, grid oxidization layers and grid electrodes, wherein the first well regions and the second well regions are formed in the substrate; the field injection regions are formed in the first well regions and the second well regions and are both overlapped with the first well regions and the second well regions; the source regions are formed in the first well regions; the drain regions are formed in the second well regions; the field oxidization layers and the grid oxidization layers cover the surface of the substrate, and the field oxidization layers are positioned above the field injection regions; and the grid electrodes are arranged between the source regions and the drain regions and are formed on the field oxidization layers and the grid oxidization layers. The second well regions and the field injection regions of the high-voltage semiconductor device together form a drift region of the high-voltage semiconductor device. When a high voltage is added at a drain end, the field injection regions overlapped with the first well regions can be exhausted, thereby the distribution of an electric field adjacent to a beak is improved, and the breakdown voltage of the semiconductor device is improved. Under the condition of not changing process flows and increasing the manufacturing cost, the breakdown voltage of the semiconductor device is improved to the maximum.

Description

technical field [0001] The invention relates to the technical field of semiconductor devices, in particular to a high-voltage semiconductor device and a manufacturing method thereof. Background technique [0002] High-voltage semiconductor devices, especially high-voltage metal oxide semiconductor (HVMOS, high voltage metal oxide semiconductor) transistors, have excellent switching characteristics, so they have been widely used in central processing unit power supplies, power management systems, DC / AC converters, and flat-panel TV drivers. , and consumer electronics and other fields. [0003] For high-voltage semiconductor devices, maximizing their breakdown voltage is the direction that the industry has been striving for. For example, high-voltage PMOS transistors often adopt an extended drain structure. This transistor uses a diffused doped region with a small concentration as the drift region of the PMOS transistor to extend its drain to withstand high voltages and cover...

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Problems solved by technology

However, since the junction depths of the P-well region 23 and the N-well region 22 are similar, and the doping concentration is basically the same, when a voltage is applied, the P-well region 23 cannot be completely depleted, so the breakdown still occurs near the bird's beak of the drain terminal. , is a lateral breakdown, and its breakdown voltage is still lower than the breakdown voltage between the P well region 23 and the N-type buried layer 21 (72V)

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