Ion implantation method of substrate back of power device

Abstract

The invention relates to an ion implantation method of a substrate back of a power device, belonging to the technical field of semiconductor power devices. The ion implantation method disclosed by the invention comprises the following steps of: after finishing steps of a front face process of the power device, thinning the substrate back to an impurity implantation layer and then depositing a metal aluminum layer by utilizing a corrosion or grinding method after ion implantation (thinning or non-thinning process can be carried out on the substrate back before the ion implantation) and ion activation are finished, but not directly carrying out metal aluminum layer deposition like the traditional process. Therefore, the contact resistance between the subsequently deposited metal aluminum and the substrate can be reduced, unnecessary parasitic multi-layer structures can be eliminated, the leakage current and the on-state voltage drop of the power device are reduced, and the switching time of the power device is shortened. The ion implantation method of the substrate back of the power device, disclosed by the invention, is suitable for semiconductor power devices made from semiconductor materials, such as bulk-silicon, silicon carbide, gallium arsenide, indium phosphide or germanium silicon and the like.

Description

technical field [0001] The invention belongs to the technical field of semiconductor power devices and relates to the manufacturing technology of semiconductor power devices. Background technique [0002] Power semiconductor technology is the core of power electronics technology. With the development of microelectronics technology, modern power semiconductor technology represented by gate-controlled power devices and intelligent power integrated circuits has developed rapidly since the 1980s, which has greatly promoted Advances in power electronics. The continuous progress of power electronics technology in turn promotes the development of power semiconductor technology in the direction of high frequency, high temperature, high voltage, high power, intelligence and systematization. After more than 40 years of development, power semiconductor devices have continued to improve in device manufacturing technology. They have experienced discrete devices represented by thyristors...

AI Technical Summary

Problems solved by technology

The mainstream manufacturing process of the above-mentioned various power devices is to directly manufacture metal electrodes after impurity ion implantation and annealing. However, after impurity implantation on the back of the silicon wafer, an impurity distribution layer with a certain depth will be formed after annealing activation. The impurity layer will cause the back metal and the implanted impurity region to fail to form a good ohmic contact, bring unnecessary parasitic multi-layer structure, increase the leakage current, on-state voltage drop and switching time of the power device, and directly lead to the developed Power devices cannot be used

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