Manufacture method of Zener diode

Abstract

The invention discloses a manufacture method of a Zener diode. The manufacture method comprises the steps of: providing a substrate with an epitaxial layer; etching the epitaxial layer and partial thickness of substrate to form a first annular deep groove; forming an insulation layer on the epitaxial layer while forming a first deep groove filling; etching the epitaxial layer and partial thickness of substrate, forming at least one second deep groove in a region enclosed by the first deep groove; forming in situ doped polycrystalline silicon on the imaged insulation layer while forming a second groove filling; annealing the substrate to form a diffusion region, wherein the diffusion region and the substrate form a PN junction of the Zener diode; etching in situ doped polycrystalline silicon to form the imaged polycrystalline silicon to be used as a cathode of the Zener diode; and forming a metal layer on the back surface of the substrate, wherein the metal layer is used as an anode of the Zener diode. According to the invention, the deep groove process is used for replacing the traditional high-temperature diffusion method, thus the area of a device can be greatly reduced and the integrated level of the integrated circuit is improved.

Description

technical field [0001] The invention relates to the field of integrated circuit manufacturing, in particular to a method for manufacturing Zener diodes. Background technique [0002] Transient interference of voltage and current is the main cause of damage to electronic circuits and equipment, and often brings incalculable losses to people. These disturbances usually come from the start-stop operation of power equipment, the instability of the AC power grid, lightning strike interference, electrostatic discharge and other transient disturbances that are almost everywhere and all the time, making people feel hard to guard against. A transient voltage suppressor (Transient Voltage Suppressor, TVS) is a high-efficiency protection device in the form of a diode. When the two poles of the TVS diode are impacted by reverse transient high energy, it can change the high impedance between its two poles to low impedance at a speed of 10 minus 12 seconds, absorbing surge power up to se...

AI Technical Summary

Problems solved by technology

Although this process is simple, it increases the packaging cost and is not conducive to reducing the size of the device.

Another existing technology for integrating Zener diodes and PIN diodes is to grow a high-resistivity N-type epitaxial layer on a highly doped P-type substrate, and diffuse N-type impurities through the N-type epitaxial layer through high-temperature diffusion. layer, forms a zener diode with the P-type substrate under the epitaxial layer, which requires a long high-temperature diffusion process, which leads to a very large area of ​​lateral diffusion, and needs to be isolated by a PN junction, which will make the device area becomes very large

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