Semiconductor device and preparation method thereof

Abstract

The invention relates to a semiconductor device and a preparation method thereof. The preparation method comprises the steps that a body region is formed in a drift region, and a first doped region and a second doped region are formed in the body region; a first trench penetrates through the first doped region and the body region and extends into the drift region, an expansion region is opposite to the drift region in conduction type and surrounds the bottom wall of the first trench, and the first trench is filled with a dielectric layer formed on the side wall of the trench, a first conductive structure located at the bottom of the trench and a second conductive structure located at the top of the trench; and a second trench penetrates through the body region and extends into the drift region, and the second trench is filled with a third conductive structure and a dielectric layer located on the inner wall of the trench. The second conductive structure is electrically connected with the grid electrode, and the first doped region, the second doped region and the third conductive structure are electrically connected with a first electrode. Through the combined action of a first trench gate, the expansion region and a trench adjustment region, the depletion of the drift region can be enhanced, and the withstand voltage of the device is improved.

Description

technical field [0001] The present application relates to the field of semiconductors, in particular to a semiconductor device and a manufacturing method thereof. Background technique [0002] In MOS (Metal Oxide Semiconductor, Metal Oxide Semiconductor) tubes and other semiconductor devices integrated with MOS tube structures, there will be a certain on-resistance when the device is turned on, the greater the on-resistance, the greater the power consumption of the device , therefore, it is necessary to minimize the on-resistance. At present, a trench gate structure is usually used. By forming a trench gate structure, the conduction channel is changed from horizontal to vertical, which greatly increases the density of the conduction channel and reduces the on-resistance. However, on the basis of the trench gate structure, if you want to further reduce the on-resistance, you need to increase the doping concentration of the drift region, and increasing the doping concentratio...

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Problems solved by technology

[0003] Based on this, it is necessary to propose a new semiconductor device and its preparation method for the technical problem that it is difficult to further reduce the on-resistance of the current semiconductor device.

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