Shield gate groove type field effect transistor with variable doping structure and preparation method of shield gate groove type field effect transistor

Abstract

The invention relates to a shield gate trench type field effect transistor with a variable doping structure. The shield gate trench type field effect 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 doping type of the substrate region 1, the drift region 2 and the source region 7 is a first doping type; the doping type of the substrate region 6 is a second doping type; the doping concentration of the substrate region 1 and the doping concentration of the source region 7 are both larger than the doping concentration of the drift region. The base body region 6 comprises a plurality of doped distribution layers which are distributed from top to bottom; and the doping concentration of the plurality of doping distribution layers is linearly reduced from top to bottom. According to the scheme provided by the invention, the channel length of the channel region can be effectively shortened, so that the on-resistance of the channel region is reduced.

Description

technical field [0001] The present application relates to the field of semiconductor technology, in particular to a variable doping structure 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] When the breakdown voltage is less than 300V, especially when the breakdown voltage is less than 100V, or even less than 40V, the channel region and the drift region have comparable specific on-resistance. Therefore, for low-voltage shielded gate trench type For field effect transistors, the improvement of ...

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Problems solved by technology

[0005] However, the above scheme is a structural improvement of the drift region of the transistor, which has a significant effect on improving the breakdown voltage of the transistor, and has a low impact on the specific on-resistance of the channel region, and cannot meet the low-voltage level shielding gate trench type field. The need for effect transistors to reduce specific on-resistance

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