Silicon carbide trench IGBT structure and manufacturing method thereof

Abstract

The invention discloses a silicon carbide trench IGBT structure, and the structure comprises an N-drift region, an N-type buffer layer, a P-type well region, a P+ ohmic contact region, an N+ emitter region, a P+ trench collector region, a trench collector, a P+ collector region, an N+ substrate layer, a trench gate and a gate oxide dielectric layer. Compared with a traditional structure, the structure is additionally provided with the trench collector on the collector, and is also additionally provided with the P+ trench collector above the trench collector; due to a fact that no N+ buffer layer is arranged above the P+ trench collector region of the new device, the hole injection efficiency during forward conduction is enhanced, and the turn-on voltage of the new device is reduced; when the new device is turned off, the trench collector provides a low-resistance channel, so the extraction of electrons is accelerated, and the turn-off loss is further reduced.

Description

technical field [0001] The invention relates to the technical field of insulated gate bipolar transistor devices, in particular to a high-voltage silicon carbide trench IGBT structure with a voltage greater than 15kV and a manufacturing method thereof. Background technique [0002] IGBTs is a composite tube composed of MOSFET and BJT, which combines the advantages of MOSFET and BJT, and is an ideal switching device. The excellent material properties of SiC, such as 3 times wider band gap, 10 times higher critical field strength, 3 times higher thermal conductivity and 2 times higher carrier saturation velocity, make SiC-based semiconductor devices widely used. The application of high temperature, high pressure, high power and other applications. In addition, since the characteristic on-resistance of unipolar devices is proportional to the 2.5th power of its breakdown voltage, SiC MOSFETs are not suitable for application in the field of breakdown voltage > 10kV. Due to t...

AI Technical Summary

Problems solved by technology

[0003] However, due to the conductance modulation effect during forward conduction, although the on-state voltage drop of the device can be reduced, a large number of electron-hole pairs are stored in the drift region at the same time.

When turning off, these excess carriers stored in the drift region need a certain amount of time to be completely extracted and recombined, which will cause a long current tail of the device and increase the turn-off loss of the device

Images