A structure of high-voltage sic IGBT that suppresses dv/dt, di/dt noise generation

Abstract

The invention provides a high-voltage SiC IGBT structure that suppresses dv / dt and di / dt noise. The improved semiconductor structure includes: a P-type injection layer in contact with the anode ohmic electrode, and an N buffer in contact with the upper surface of the P-type injection layer layer, the N-drift layer in contact with the upper surface of the N-buffer layer, and the current spreading layer in contact with the upper surface of the N-drift layer; wherein, the doping concentration of the N-drift layer is currently the typical concentration of the withstand voltage layer of the current high-voltage silicon carbide device 1.2 to 4 times; the N buffer layer is divided into multiple regions, and its concentration increases from the P+ injection layer to the N-drift layer. In view of the problem of strong dv / dt and di / dt noise of SiC IGBT in the prior art, the semiconductor structure provided by the present invention will be able to limit the depletion region in the turn-off transient process to the drift layer, effectively avoiding punch-through effect, thereby greatly suppressing dv / dt, di / dt noise generation, while stabilizing power loss within a reasonable range.

Description

technical field [0001] 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. Background technique [0002] 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 years, the research and de...

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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 ~ 2e14cm -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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