A trench-gate vdmos device with integrated schottky diode

Abstract

A trench gate VDMOS device integrating Schottky diodes belongs to the technical field of semiconductor devices. In the present invention, an additional structure composed of Schottky junction metal and body electrode conductive material is respectively added to the drift region on both sides of the groove gate structure of the conventional groove gate VDMOS device; It is in contact with the conductive material of the body electrode, and the rest of the lower surface and side parts are in contact with the drift region to form a Schottky junction; the side and bottom surfaces of the conductive material of the body electrode and the drift region are separated by a layer of dielectric layer. Compared with the traditional trench-gate VDMOS device with the same size, the present invention can adopt a higher doping concentration in the drift region under the same breakdown voltage, so the on-resistance is significantly reduced, and the reverse recovery characteristic of the diode is significantly improved. improvement.

Description

technical field [0001] The invention belongs to the technical field of semiconductor devices, and relates to a trench gate VDMOS device, in particular to a trench gate VDMOS device integrated with a Schottky diode. Background technique [0002] VDMOS is the most widely used type of power device in power semiconductors. It has the advantages of easy driving, fast switching speed, integration, and simple process. In the low-voltage field, the trench-gate VDMOS device is widely used because it eliminates the resistance of the JFET region and has a smaller cell size, so it has a lower specific on-resistance. [0003] The basic N-channel trench-gate VDMOS device structure is as figure 1 As shown, it includes: source metal 1, isolation dielectric 3, N+ source region 4, P-type base region 5, P+ body contact region 6, polysilicon gate electrode 9, gate dielectric layer 10, N-drift region 11, N+ liner bottom 12 and drain metal 13. VDMOS devices are often used as switching devices....

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Problems solved by technology

The reverse recovery of the body diode has a greater impact on the switching process of the VDMOS device, especially during the turn-on process of the VDMOS device, the reverse recovery process of the body diode may cause overshoot of current and voltage, resulting in dynamic failure of the device, and worse Unfortunately, the fabrication techniques of VDMOS devices usually result in higher carrier lifetime and thus higher stored charge and larger diode peak reverse current, so the body diode has worse reverse recovery characteristics, which further deteriorates the switching characteristics of VDMOS devices

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