A kind of low overshoot voltage unidirectional TVS and its manufacturing method

Abstract

The invention discloses a low overshoot voltage unidirectional TVS, which comprises a P-type substrate and an N+ concentrated phosphorus region diffused on the upper and lower surfaces of the P-type substrate, and the N+ concentrated phosphorus region covers the upper and lower surface areas of the P-type substrate respectively. 2 / 3-5 / 6; the upper surface of the TVS device is oxidized with a silicon dioxide passivation layer, the upper surface of the TVS device is provided with a metal electrode K, and the lower surface of the TVS device is provided with a metal electrode A; the invention also discloses the low A method for manufacturing an overshoot voltage unidirectional TVS, comprising the following steps: step S1, substrate preparation; step S2, oxidation; step S3, photolithography of the concentrated phosphorus region; step S4, diffusion of the concentrated phosphorus region; step S5, photolithography of the lead hole ; Step S6, steaming aluminum; Step S7, aluminum reverse etching; Step S8, steaming aluminum alloy; Step S9, steaming Ti-Ni-Ag alloy; Step S10, Ti-Ni-Ag reverse etching. Compared with the unidirectional TVS of the traditional structure, the present invention has one more concentrated phosphorus diffusion region and one less boron concentration diffusion region in structure, and diffuses the concentrated phosphorus region on the lower surface of the P-type substrate, which can effectively reduce the overshoot voltage and enhance the device. surge capability.

Description

technical field [0001] The invention belongs to the field of semiconductor protection devices, and in particular relates to a low overshoot voltage unidirectional TVS and a manufacturing method thereof. Background technique [0002] The TVS device is a voltage-limiting transient voltage protection diode, which can clamp the surge voltage within a certain safe value with ns response speed. TVS is usually used in some protection circuits in parallel in the line. like figure 2 As shown, the traditional unidirectional TVS device includes a P-type substrate, an N+ concentrated phosphorus region located on the upper surface of the P-type substrate, a P+ rich boron region located on the lower surface of the P-type substrate, and a silicon dioxide layer located on the upper surface of the device. Passivation layer, metal electrode K on the upper surface of the device and metal electrode A on the lower surface. When K is at a high potential relative to A and the potential reaches t...

AI Technical Summary

Problems solved by technology

[0003] For applications with high inrush current, the inrush current is very large, and a high overshoot voltage will appear at both ends of the conventional unidirectional TVS, which seriously threatens the safety and working stability of the protected line at the back end, especially when TVS is used in This is especially true for the protection of voltage sensitive lines

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