A trench type vdmos

A trench type, trench technology, applied in semiconductor devices, electrical components, circuits, etc., can solve the problems of high source-drain capacitance Cds, restricting reverse withstand voltage, affecting the dynamic characteristics of devices, etc. The effect of increasing the reverse blocking voltage
CN106298937BInactive Publication Date: 2019-02-01UNIV OF ELECTRONICS SCI & TECH OF CHINA
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
UNIV OF ELECTRONICS SCI & TECH OF CHINA
Publication Date
2019-02-01
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention belongs to the technical field of semiconductors, in particular to a trench type VDMOS device. The invention mainly has a polysilicon column wrapped by a silicon dioxide layer in a groove in the body, and uniform negative charges are stored in the polysilicon column. The shape of the polysilicon column is wide at the top and narrow at the bottom, and the thickness of the silicon dioxide between it and the silicon wafer increases from top to bottom. When the device is reverse-blocked, a lateral electric field is generated between the N-type drift region and the negative charges in the polysilicon pillar to assist in depleting the drift region. Since the potential of the N-type drift region gradually decreases from bottom to top, and the thickness of silicon dioxide on the sidewall of the polysilicon column increases from top to bottom, the lateral electric field distribution in the drift region is more uniform, so that the vertical electric field is closer to the rectangular distribution, improving The reverse blocking voltage of the device. At the same time, since the body field plate structure connected to the source electrode is not used, the gate-to-drain capacitance Cds in the present invention is relatively low.
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Description

technical field

[0001] The invention belongs to the technical field of semiconductors, in particular to a trench type VDMOS device. Background technique

[0002] Power VDMOS is a multi-subconductor device, which has the advantages of fast switching speed, high input impedance, and easy driving. An ideal VDMOS should have low on-resistance, switching loss and high blocking voltage. However, there is a restraint effect between on-resistance and breakdown voltage, on-resistance and switching loss, which limits the development of power VDMOS. In order to improve device performance and reduce on-resistance, academician Chen Xingbi proposed a super-junction VDMOS structure. Compared with the traditional structure, the super-junction structure obtains a better trade-off relationship between device withstand voltage and on-resistance. Under the same device withstand voltage condition, the on-resistance of VDMOS with super-junction structure is smaller.

[0003] Since the super-ju...

Claims

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