Semiconductor element and preparation method thereof

Abstract

The embodiment of the invention discloses a semiconductor element and a preparation method thereof. In the semiconductor element, one side, far away from a substrate, of an epitaxial layer comprises a groove; the oxide layer is located in the groove; the grid polycrystalline silicon layer and the source polycrystalline silicon layer are embedded in the oxide layer, the grid polycrystalline silicon layer and the source polycrystalline silicon layer are separated by the oxide layer, and the oxide layer at least exposes the surface, away from the substrate, of the grid polycrystalline silicon layer; the body region and the source region are both formed in one end, far away from the substrate, of the epitaxial layer, the body region and the source region are both located on the left side and the right side of the grid polycrystalline silicon layer, and the body region is located on the side, close to the substrate, of the source region relative to the source region; the source electrode is located on the side, away from the substrate, of the body region and electrically connected with the source region; the source electrode polycrystalline silicon layer is electrically connected with the source electrode, and the type of doped ions of the source electrode polycrystalline silicon layer is opposite to that of doped ions of the grid electrode polycrystalline silicon layer; therefore, the total quantity of charges required by the MOSFET during reverse recovery of the body diode is reduced, and the peak of drain-source voltage VDS is reduced.

Description

technical field [0001] Embodiments of the present invention relate to the technical field of semiconductors, and in particular, to a semiconductor element and a manufacturing method thereof. Background technique [0002] Compared with the traditional Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), the deep channel MOSFET has a better figure of merit (FOM). Due to the coupling balance design, the split gate power MOSFET can realize low on-resistance and low reverse transmission capacitance at the same time, thereby reducing the conduction loss and switching loss of the system and improving the efficiency of electronic products. [0003] However, in practical applications, such as resonant topology power supply or brushless motor applications, the reverse recovery of the MOSFET body diode will be experienced during each switching process. When the body diode reverses recovery, the drain-source voltage VDS tends to spike too much and thus Directly lead to MOSFET ov...

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Problems solved by technology

[0003] However, in practical applications, such as resonant topology power supply or brushless motor applications, the reverse recovery of the MOSFET body diode will be experienced during each switching process. When the body diode reverses recovery, the drain-source voltage VDS tends to spike too much and thus Directly lead to MOSFET overvoltage failure

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