High-voltage SiC IGBT structure capable of inhibiting noise generation of dv/dt and di/dt

Abstract

The invention provides a high-voltage SiC IGBT structure for inhibiting dv / dt and di / dt noises. The improved semiconductor structure comprises a P type injection layer in contact with an anode ohmic electrode, an N buffer layer in contact with the upper surface of the P type injection layer, an N drift layer in contact with the upper surface of the N buffer layer, and a current expansion layer incontact with the upper surface of the N drift layer, wherein the doping concentration of the N drift layer is 1.2-4 times the typical concentration of the voltage-withstanding layer of the high-voltage silicon carbide device at present, the N buffer layer is divided into a plurality of regions, and the concentration of the N buffer layer increases progressively from the P+ injection layer to the Ndrift layer. According to the invention, based on the high noise of dv / dt and di / dt of SiC IGBT in the prior art, the semiconductor structure provided by the invention can limit the depletion regionin the turn-off transient process in the drift layer so as to effectively avoid the punch-through effect from being generated, so that the generation of dv / dt and di / dt noises is greatly inhibited while the power loss can be stabilized within a reasonable range.

Description

[0001] 1. Technical field [0002] The invention relates to the technical field of high-voltage power electronics, in particular to a structure of a high-voltage SiC IGBT that suppresses dv / dt and di / dt noises. [0003] 2. Background technology [0004] Insulated Gate Bipolar Transistor (IGBT) is a bipolar device composed of a power MOSFET and a bipolar transistor, which combines a MOS gate structure that facilitates simplified driving and has a conduction loss The excellent performance of low temperature and fast switching speed has been relatively mature in the field of traditional silicon (Si) materials. Silicon Carbide (SiC) is a third-generation wide-bandgap semiconductor material. Compared with silicon materials, it has 10 times the breakdown electric field, 3.3 times the thermal conductivity, and 2 times the saturation carrier drift velocity. It is considered to be an ideal material for preparing high temperature, high frequency and high voltage devices. In recent year...

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Problems solved by technology

The structure grows buffer layers in two or more regions by epitaxial growth, and its concentration shows a decreasing trend from the P+ injection layer to the N-drift layer, but the concentration of the drift region is the typical value of the current SiC high-voltage device ~2e14 cm -2 , the drift layer voltage determined by its concentration is still low, and it will also produce a strong punch-through effect during the turn-off transient process, so this structure has very limited suppression effect on dv / dt, di / dt noise, and due to the thickness of the buffer layer , which increases the forward voltage drop and increases the power loss, thus further limiting the practical application of the structure

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