Trench mosfet and manufacturing method of the same

Abstract

A trench MOSFET and a manufacturing method of the same are provided. The trench MOSFET includes a substrate, an epitaxial layer having a first conductive type, a gate in a trench in the epitaxial layer, a gate oxide layer, a source region having the first conductive type, and a body region and an anti-punch through region having a second conductive type. The anti-punch through region is located at an interface between the source region and the body region, and a doping concentration thereof is higher than that of the body region. The epitaxial layer has a first pn junction near the source region and a second pn junction near the substrate. N regions are divided into N equal portions between the two pn junctions, and N is an integer greater than 1. The closer the N regions are to the first pn junction, the greater the doping concentration thereof is. Each of the N regions has a doping concentration integral area, and the doping concentration integral area of the region closer to the first pn junction in the N regions is larger. Through the breakdown-resistant doped region, the device has steep concentration distribution, so that the UIS capability of the device is improved.

Description

technical field [0001] The invention relates to a power semiconductor device, in particular to a trench type metal oxide semiconductor field effect transistor element and a manufacturing method thereof. Background technique [0002] Among power semiconductor devices, power semiconductor devices vertically arranged in trenches have become one of the focuses of development in various fields because they can greatly increase unit density. [0003] figure 1 It is a schematic diagram of a known trench metal oxide semiconductor field effect transistor device. exist figure 1 In the epitaxial layer 102 on the substrate 100, there are a source region 104 and a body region 106, while a trench gate 108 is disposed in the epitaxial layer 102, and an inner layer dielectric layer (ILD) 110 covers the epitaxial layer 102 and trenched gate 108 . In addition, there is a gate oxide layer 112 on the surface of the trench gate 108 . [0004] figure 2 is along figure 1 The doping concent...

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Problems solved by technology

Once the body resistance becomes high, it will easily cause the parasitic N (source 104)-P (body 106)-N (epitaxial layer 102) bipolar transistor to be turned on, and the MOSFET will undergo secondary breakdown (Secondary breakdown), causing the temperature of the device to rise , causing permanent damage to the device, that is, the performance of the Unclamped Inductive Switching (UIS) deteriorates

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