Structure of a superjunction mosfet device

Abstract

The invention discloses a structure of a super junction MOSFET device, wherein the width ratio S1 of the first semiconductor layer and the second semiconductor layer in the active region, the width ratio S2 of the first semiconductor layer and the second semiconductor layer in the terminal region, and the active region and the doping concentration m of the first semiconductor layer in the terminal area, and the doping concentration n of the second semiconductor layer in the active area and the terminal area, satisfying the conditions: 0<1‑S1m / n≤0.1 and‑0.1≤1‑S2m / n <0; or -0.1≤1‑S1m / n<0 and 0<1‑S2m / n≤0.1. In the present invention, the width ratio and doping concentration ratio of the first semiconductor layer and the second semiconductor layer in the active region and the terminal region are reasonably designed, so that the breakdown voltage of the active region and the terminal region is distributed in a certain difference range In this way, the breakdown voltage range is reduced, and the uniformity of breakdown voltage and the uniformity of super junction MOSFET devices are improved.

Description

technical field [0001] The invention relates to the field of integrated circuit manufacturing, in particular to the structure of a super junction MOSFET device. Background technique [0002] VDMOSFET (vertical double-diffused MOS transistor) can reduce the on-resistance by reducing the thickness of the drain drift region. However, reducing the thickness of the drain drift region will reduce the breakdown voltage of the device. Therefore, in VDMOS, increase The breakdown voltage of the device and the reduction of the on-resistance of the device are a pair of contradictions. [0003] The super junction MOSFET adopts a new voltage-resistant layer structure, which uses a series of alternately arranged P-type and N-type semiconductor thin layers to deplete the P-type and N-type regions at a lower reverse voltage to achieve mutual charge compensation. As a result, the P-type and N-type regions can achieve high breakdown voltage under high doping concentration, so that low on-resi...

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Problems solved by technology

[0004] However, it is difficult to control the stability of the doping concentration of the super junction MOSFET

Usually, the P / N width ratio of the active region and the terminal region of the device are consistent, and the breakdown voltage distributions of the active region and the terminal region are also consistent (see figure 1 ), the breakdown voltage of the device depends on the breakdown voltage of one of them, which is t3 to t1, which leads to a relatively large fluctuation of the breakdown voltage and poor stability of the device

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