Method for preparing punch-through type silicon carbide insulated gate bipolar transistor

Abstract

The invention discloses a method for preparing a punch-through type silicon carbide insulated gate bipolar transistor. The method mainly solves the problem that at present, the preparing cost of the silicon carbide insulated gate bipolar transistor is too high. The method comprises the implementing steps that (1) a P-type silicon carbide substrate with good structural performance is selected, the back surface of the substrate is cut and thinned, and a cut surface is polished and oxidized; (2) an N well region, an N+ body contact region, a JFET region and a P+ emitter region are formed on the front surface of the substrate in sequence through ion implantation; (3) ion implantation is carried out on a buffer layer and a collector electrode region on the back surface of the substrate; (4) high temperature annealing is carried out, activation is carried out, and dopants are implanted; (5) a grid oxidation layer is grown and etched on the front surface of the substrate, and a polysilicon gate is deposited on the front surface of the substrate; (6) metal deposition and photoetching are carried out on the front surface and the back surface of the substrate, and electrodes are led out. Compared with an existing method, the epitaxial growth of an over-thick withstand voltage layer is not needed, a large amount of production cost is saved, processing steps are simplified, and the method can be applied to the fields of inverters, switch power supplies and illumination circuits.

Description

Technical field [0001] The invention belongs to the field of microelectronics technology, and relates to a method for preparing semiconductor devices, in particular a punch-through SiC IGBT that uses a substrate as a withstand voltage layer, and can be widely used in frequency converters, inverters, switching power supplies, lighting circuits and motors And other fields. technical background [0002] Silicon carbide insulated gate bipolar transistors, namely SiC IGBTs, are new high-voltage resistant devices developed based on silicon carbide materials. At present, the mainstream solid-state device used in the field of power electronics is Si IGBT with a turn-off voltage of 0.6-6.5kV. After 30 years of development, Si IGBT has reached the limit of performance and device structure. With the development of new applications such as electric vehicles, photovoltaic and wind energy green energy, and smart grids, new leap in the performance of power electronic devices is required. In t...

AI Technical Summary

Problems solved by technology

[0007] 1. High preparation cost

For example, SiC epitaxial equipment is expensive, and the epitaxial process consumes a lot of energy, etc.

[0008] 2. The technical difficulty of growing a thicker SiC epitaxial layer is high. For example, for the growth of an epitaxial layer with a thickness of 100 μm and above, the process requirements are high. Only top silicon carbide device companies such as Cree can do it in the world. Therefore, the technology The bottleneck problem limits the popularization and application of high-power SiC IGBT

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