Trench metal oxide semiconductor (MOS) device with reinforced grid bus and production method thereof

Abstract

The invention discloses a trench metal oxide semiconductor (MOS) device with reinforced grid bus and a production method thereof. The device comprises an active area positioned on the middle portion and a grid bus area positioned at the periphery and surrounding the active area. A plurality of trench MOS unit cells which are arranged repeatedly are arranged in parallel to form the active area, grid trenches are arranged in each of the trench MOS unit cells, the inner walls of the grid trenches are coated by grid oxide layers, a plurality of grid bus trenches are arranged in the grid bus area, the grid bus trenches are in mutual communication with the grid trenches, the grid bus trenches are coated by isolation oxide layers, the thickness of the isolation oxide layers is larger than that of the grid oxide layers, a doping strengthening area is arranged in epitaxial layers of the bottom of the grid bus trenches, and the doping concentration of the doping strengthening area is higher than that of the epitaxial layers. The trench MOS device with reinforced grid bus improves performance of trench MOS devices and reliability of devices by reinforcing grid bus.

Description

technical field [0001] The invention relates to a power MOS field effect transistor and a manufacturing method thereof, in particular to a gate bus reinforced trench MOS field effect transistor device and a manufacturing method thereof. Background technique [0002] Trench MOS devices are widely used in power circuits as switching devices to connect power and loads. like figure 1 As shown, in the trench MOS device, the smallest repeating unit including the gate trench 6 and the source region 7 is called a unit cell, and these unit cells are arranged periodically to form the active region 1 . A source contact hole 15 is provided on each unit cell source region 7 in the active region 1 . On the periphery of the active area 1 , a trench MOS gate bus area 2 is arranged around the active area 1 . A gate bus trench 10 is arranged in the gate bus region 2 and communicates with the gate trench 6 in the active region 1 . Each gate bus trench 10 is provided with a gate contact hol...

AI Technical Summary

Problems solved by technology

The strong electric field will cause premature failure of the oxide layer at the bottom of the gate bus trench 10, affecting device life and reliability

At the same time, the strong electric field will be introduced into the central region in the epitaxial layer at the bottom of the gate bus trench 10, resulting in large device leakage and affecting device performance and reliability.

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