Semiconductor device and manufacturing method thereof

Abstract

The invention provides a semiconductor device and a manufacturing method thereof, and the semiconductor device comprises a drift region which is located between a body region and a drain region and isformed on a substrate; a trench which vertically extends into the drift region from the upper surface of the drift region; a trench insulation filling structure set in the trench; a field insulationdielectric layer which is at least formed above part of the trench insulation filling structure and transversely extends to the position above the drift region close to one side of the body region soas to cover the junction of the top end of the side wall of the trench and the upper surface of the drift region located on one side of the body region; and a grid electrode which comprises a grid dielectric layer and a grid structure formed on the grid dielectric layer, wherein the grid dielectric layer transversely extends to the upper part of the trench insulation filling structure from the upper part of the drift region so as to at least partially cover the field insulation dielectric layer. According to the technical scheme of the invention, the breakdown voltage of the semiconductor device can be improved under the condition that the on-resistance is not increased.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a semiconductor device and a manufacturing method thereof. Background technique [0002] Trench type metal oxide semiconductor field effect transistor (Trench MOSFET) has been widely used in various integrated circuits, see figure 1 , figure 1 is a schematic diagram of the structure of a trench metal-oxide-semiconductor field-effect transistor, from figure 1 It can be seen from the figure that a P-type body region 11, a N-type drift region 12, a trench insulation filling structure 13, and a P-type body region 11 are formed in a P-type substrate 10. A body contact region 14, a source region 15 whose conductivity type is N-type, and a drain region 16 whose conductivity type is N-type, wherein the body region contact region 14 and the source region 15 are formed in the body region 11, and the drift region 12 is adjacent to the body region 11, and the ...

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Problems solved by technology

but, figure 1 The disadvantage of the structure in is that the junction between the gate oxide layer 17 and the top of the sidewall of the trench insulation filling structure 13 is easily broken down in advance, resulting in a decrease in the breakdown voltage of the device

In order to improve the breakdown voltage of the device, the existing approach is to reduce the ion implantation dose in the drift region 12, or reduce the size of the drift region 12 surrounding the trench insulation filling structure 13; but these two methods will lead to the conduction of the device. On-resistance (Ron) increases rapidly

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