Power chip preparation method and power chip

Abstract

The invention provides a power chip preparation method and a power chip. The method comprises: forming an N-type cut-off ring (41) on the front surface of an N-drift layer (1), forming a transition region (3) and a P-type withstand voltage ring (42) on the front surface of the N-drift layer (1) according to different doping concentrations, and forming an active region (2) on the front surface of the N-drift layer (1), wherein the doping concentration of the transition region (3) close to the active region (2) is larger than the doping concentration of the transition region (3) close to the P-type voltage-withstanding ring (42), and the doping depth of the transition region (3) close to the active region (2) is larger than the doping depth of the transition region (3) close to the P-type voltage-withstanding ring (42). According to the power chip, the gradient doped transition region (3) is formed on the front surface of the N-drift layer (1) through different doping concentrations, sothat improvement of electric field distribution of the transition region is facilitated, the electric field intensity can be effectively reduced, the hole current density of the transition region whenthe IGBT is turned off is reduced, the region is prevented from being burnt by heat, the overcurrent turn-off capability is improved, and the firmness of the IGBT power chip is improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor devices, in particular to a method for preparing a power chip and the power chip. Background technique [0002] In power chips such as metal-oxide semiconductor field effect transistors (Metal Oxide Semiconductor, MOSFET) or insulated gate bipolar transistors (Insulated Gate Bipolar Transistor, IGBT), there is a transition zone structure similar to a diffusion guard ring at the outermost cell , that is, the transition region structure is a region between the active region and the terminal region of the power chip; it is also called the main junction. [0003] In the case of high-current shutdown of inductive loads, the IGBT power chip is easily burned in the transition zone. The main reason is that during the turn-off transient process, there is uneven distribution of current, electric field and heat inside the entire IGBT power chip; especially in the transition area, it is easy to form el...

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the shortcomings of the above-mentioned complex process in the prior art, the present invention provides a method for preparing a power chip, including:

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