Insulated gate bipolar transistor and preparation method thereof

Abstract

The invention discloses an insulated gate bipolar transistor and a preparation method thereof. The insulated gate bipolar transistor comprises a semiconductor substrate and an N-drift region, wherein the N-drift region is formed by epitaxial growth on the front surface of the semiconductor substrate; an upper terminal for forming a grid and an emitter is prepared on the N-drift region; a lower terminal for forming a collector is arranged on the back surface of the semiconductor substrate; an etching groove is formed in the part, which is formed with a gate structure, on the surface of the semiconductor substrate; the etching groove is injected with a P-type dopant; and the P-type dopant diffuses to form a P-type shielding layer. The insulated gate bipolar transistor disclosed by the invention, the P-type shielding layer is added below the grid, so that the problem of a large conduction voltage drop of an existing IGBT can be relieved; electric field concentration on the curved surfaces of a P-type base region and the N-drift region in a turn-off state is eliminated; the breakdown voltage can be improved; and the reliability of the IGBT in a working process is ensured.

Description

technical field [0001] The invention relates to the technical field of transistors, in particular to an insulated gate bipolar transistor and a preparation method thereof. Background technique [0002] Insulated-Gate Bipolar Transistor (IGBT) is a power component widely used in high-voltage and high-current fields such as inverters and motor drives. It should have a blocking voltage when it is turned off, that is, a breakdown voltage (breakdown voltage) ) is high, and the conduction voltage is reduced. [0003] figure 1 What is shown is a cross-sectional view of the IGBT structure in the prior art. For the sake of simplicity and clarity of the drawings, figure 1 The section shown is the left side only, the right side is symmetrical to the left side; as figure 1 As shown, in order to have the performance of high breakdown voltage, the method of extending the physical length of the N-drift region or using a low-concentration wafer (substrate) is adopted in the prior art, bu...

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Problems solved by technology

[0005] Aiming at the above-mentioned defects existing in the prior art, the present invention discloses an insulated gate bipolar transistor and a preparation method thereof, which can alleviate the problem of large turn-on voltage drop of the existing IGBT, and eliminate the problem of the P-type base region when it is turned off. The electric field concentration generated by the curved surface of the N-drift region can increase the breakdown voltage and ensure the reliability of the IGBT during operation

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