Shield gate groove type field effect transistor and preparation method thereof

Abstract

The invention relates to a shield gate trench type field effect transistor and a preparation method thereof. The transistor comprises a substrate region, a drift region, a shield gate, a control gate, a matrix region, a source region, an insulating layer, a source electrode, a drain electrode and a metal gate electrode, the drift region, the base region, the source region and the source electrode are sequentially arranged above the substrate region, the drain electrode is arranged below the substrate region, and the control gate and the shield gate are arranged on one side of the drift region from top to bottom; the substrate region, the drift region and the source region are all N-type doped; the doping concentration of the substrate region and the doping concentration of the source region are both larger than the doping concentration of the drift region. The substrate region, the shield gate and the control gate are all P-type doped; the doping concentration of the shield grid is the same as that of the drift region; and the doping concentration of the control grid is greater than that of the shielding grid. According to the scheme provided by the invention, a peak electric field introduced by an electric field concentration effect caused by a relatively small curvature radius at a corner of the shielding grid can be effectively improved, and an effect of improving a breakdown voltage is achieved, so that the specific on-resistance of the device is reduced.

Description

technical field [0001] The present application relates to the field of semiconductor technology, in particular to a shielded gate trench type field effect transistor and a preparation method thereof. Background technique [0002] Compared with the traditional trench transistor, the shielded gate trench field effect transistor has higher channel density and better charge compensation effect, and its shielded gate structure effectively reduces the transfer capacitance, so it has a lower ratio On-resistance, smaller conduction and switching losses, and higher operating frequency are widely used in important fields such as power management. [0003] In related technologies, the contradictory relationship between breakdown voltage and specific on-resistance is an extremely important physical parameter in power devices, especially for unipolar power devices. The limitation of the breakdown voltage mainly comes from the inhomogeneity of the electric field distribution in the withs...

AI Technical Summary

Problems solved by technology

The limitation of the breakdown voltage mainly comes from the inhomogeneity of the electric field distribution in the withstand voltage region. In the traditional trench type shielded gate transistor, due to the heavy doping concentration of the shielded gate structure, when the device is in forward blocking, The electric flux of the ionized donor charge in the withstand voltage region is easy to concentrate at the corner of the shielding grid, so the large peak electric field limits the increase of the breakdown voltage

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