Trench mosfet and method of making the same

Abstract

A trench MOSFET and method of manufacturing the same are disclosed. The trench MOSFET includes: an epitaxial semiconductor layer on a semiconductor substrate; a trench extending from above the epitaxial semiconductor layer into its interior; a shielding conductor, at least a part of which is located in the lower part of the trench; an intermediate insulating layer, located above the shielding conductor; The dielectric is located on the upper sidewall of the trench; the gate conductor is located on the upper part of the trench and is separated from the shield conductor by an intermediate insulating layer; the well region is located in the epitaxial semiconductor layer and is adjacent to the trench; the source region is located in the In the well region, and adjacent to the trench; the source contact, the drain contact, the gate contact and the shielding contact are respectively electrically connected to the source region, the semiconductor substrate, the gate conductor and the shielding conductor, wherein the shielding conductor is connected to the epitaxial semiconductor layer The insulating stacks are separated by an insulating stack including at least one oxide layer and at least one nitride layer. Trench MOSFETs can improve the quality of the intermediate insulating layer, thereby increasing the breakdown voltage.

Description

technical field [0001] This invention relates to semiconductor technology, and more particularly, to trench MOSFETs and methods of manufacturing the same. Background technique [0002] Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) have been widely used as power semiconductor devices, for example as switches in power converters. [0003] A MOSFET may have a planar structure in which a source region and a drain region are formed on one side of a semiconductor substrate, and a gate conductor is located above the surface of one side of the semiconductor substrate, separated from the semiconductor substrate by a gate dielectric. MOSFETs can also have a vertical structure in which a source region is formed on one side of the semiconductor substrate, a drain region is formed on the other side, and a gate conductor extends into the interior of the semiconductor substrate, separated from the semiconductor substrate by a gate dielectric. [0004] On the basis of the ve...

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Problems solved by technology

[0007] In view of this, the object of the present invention is to provide a trench MOSFET and its manufacturing method to solve the problem in the prior art that the electrical performance of the trench MOSFET is deteriorated due to the poor quality of the intermediate insulating layer

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