A kind of field effect transistor and its manufacturing method

Abstract

The embodiment of the invention relates to the field of semiconductor technology, in particular to a field effect transistor and a manufacturing method thereof. The manufacturing method comprises the following steps: boron impurity is injected to an epitaxial layer of a substrate according to preset photoetching size to form a thick boron region; a gate oxide layer is formed in the active region of the upper surface of the epitaxial layer; gate polycrystalline silicon is formed on the upper surface of the gate oxide layer according to the preset photoetching size, and the gate polycrystalline silicon and the thick boron region are not superposed in the direction of being vertical to the substrate; and a boron P well region and a source region are formed in the epitaxial layer; and a dielectric layer and a metal layer are covered, and the field effect transistor is formed. With the adoption of the field effect transistor and a manufacturing method thereof, provided by the embodiment of the invention, through ensuring that the thick boron region and the gate polycrystalline silicon does not coincide, the gate-source leakage is avoided from being generated between the gate and the source through the boron impurity heavily-doped part of the gate oxide layer, so that the gate-source leakage probability of products is reduced.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a field effect transistor and a manufacturing method thereof. Background technique [0002] Metal-oxide-semiconductor field-effect transistor MOSFET is a common voltage-driven device with three electrodes, namely gate, source, and drain. Its working principle is: the source is grounded, the drain is connected to the power supply potential, and through The on and off of the gate voltage controls the on and off of the current between the drain and the source. [0003] The vertical double-diffused metal oxide semiconductor transistor VDMOS is a kind of MOSFET. It forms a channel through the lateral difference of the two diffusions of the P well and the source region. Because the current direction of the VDMOS flows vertically from the drain on the back to the front, it can generate high current. density, it is widely used in power semiconductor applications. Hundreds of tho...

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Problems solved by technology

Due to the thin gate oxide layer, when its quality is not high, the gate and source can easily leak through the gate oxide layer, resulting in electrical parameter failure

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