VDMOS chip for lithium battery charging system and preparation method thereof

Abstract

The invention discloses a VDMOS chip for a lithium battery charging system. The VDMOS chip comprises a substrate, a first epitaxial layer, a groove extending from the first epitaxial layer to the substrate, a second epitaxial layer and a third epitaxial layer, wherein the second epitaxial layer and the third epitaxial layer are staggered from the first epitaxial layer to the groove; the oxide layers are located on the two sides of the trench on the first epitaxial layer; the opening is located between the oxide layers; the polycrystalline silicon layer is located in the opening; the first injection region is formed in the first epitaxial layer on the two sides of the groove and connected with a part of the oxide layer, the second injection region is located in the first epitaxial layer and located on the first injection region, and the third injection region extends into the groove from the substrate and connected with the first epitaxial layer and the third epitaxial layer. The dielectric layer, the first metal layer, the second metal layer and the third metal layer are arranged on the polycrystalline silicon layer and connected with part of the second injection region. The invention further provides a preparation method of the VDMOS chip for the lithium battery charging system, so that the battery and the charging system are effectively prevented from being damaged by over-temperature, and the over-temperature feedback speed and the reliability of the lithium battery charging system are improved.

Description

technical field [0001] The invention belongs to the technical field of semiconductor chips, and in particular relates to a VDMOS chip used in a lithium battery charging system and a preparation method thereof. Background technique [0002] With the development of science and technology, lithium batteries are widely used in life, military and other fields because of their special charge and discharge characteristics. However, there are certain limitations in the use of lithium batteries. For example, when charging, if the current is not limited, the battery will overheat or even explode during the charging process, posing a great threat to personal safety. Moreover, the charging temperature of the lithium battery If it is too high, it will accelerate the reduction of battery life. Therefore, it is necessary to carry out effective thermal control and thermal management on the charging of the lithium battery to avoid the overheating of the lithium battery. For the above reaso...

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