Gamma-boron synchronous diffusion process mesa structure thyristor chip and manufacturing process thereof

Abstract

The invention discloses a gamma-boron synchronous diffusion process mesa structure thyristor chip and a manufacturing process thereof. The chip comprises an N+-type cathode region 1, a front P-type short base region, a silicon single crystal wafer and a back P-type region which are arranged from the top to bottom. Two ends of the chip are provided with communicated isolation diffusion regions, thefront surface of the chip is provided with a SiO2 protective film, and the back surface is provided with a metal electrode. The front P-type short base region of the front side of the chip is internally provided with front trenches, and the back is provided with back stress balance grooves at the communicated isolation diffusion regions. A gate aluminum electrode and a cathode aluminum electrodeare arranged between the front trenches, and the N+-type cathode region is arranged under the cathode aluminum electrode in the front P-type short base region. According to the chip and the manufacturing process, the characteristic that a gallium diffusion coefficient is larger than a boron diffusion coefficient is utilized, a gamma-boron synchronous diffusion process is used, low vivo concentration and low capacitance can be obtained, thus a breakdown voltage VBR is close to a switch-on voltage VBO, a high surface concentration and short base region lateral resistance can be obtained, at thesame time, the diffusion time is short, and the production cost is saved.

Description

technical field [0001] The invention relates to the technical field of manufacturing power semiconductor devices, in particular to a gallium-boron synchronous diffusion process mesa-structure thyristor chip and a manufacturing process thereof. Background technique [0002] In the existing thyristor, when the voltage between the cathode and the anode exceeds a certain value, or a current of a certain value is applied between the cathode and the gate level, the thyristor is quickly turned on. [0003] In order to improve the dv / dt capability of the thyristor and prevent false conduction, the structure of the short-circuited emitter cathode is often adopted. In fact, the design of the short-circuit point is various. Now, a single model is used to discuss the relationship between the maintenance current and the device parameters. . According to the analysis results of the P.S.Radercht model, the maintenance current IH is: [0004] IH=(2πV K W 2 ) / (ρ 2 ln(b / a)) [0005] Amo...

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Problems solved by technology

[0007] However, this type of traditional process has the following disadvantages: the high-temperature diffusion time of the coated source boron expansion process is long, the capacitance is high, and αnpn is small, resulting in a large difference between the breakdown voltage VBR and the conduction voltage VBO, which deteriorates the characteristics and slows the turn-on speed. ; and open tube gallium expansion process although the time is short, VBR is close to the turn-on voltage VBO, but the lateral resistance of the short base area is relatively large, which is not conducive to the manufacture of thyristors with large sustain or large trigger, and it is difficult to meet the application requirements

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