Large-current low-forward-voltage-drop silicon carbide Schottly diode chip and preparation method thereof

Abstract

The invention provides a large-current low-forward-voltage-drop silicon carbide Schottly diode chip. The large-current low-forward-voltage-drop silicon carbide Schottly diode chip comprises a back laminated metal electrode, a front laminated metal electrode, an ohmic contact layer, a substrate, a first epitaxial layer, a second epitaxial layer, a P-type protecting ring, a N-type ion implanted layer, a Schottly metal Pt layer, an annular passivation layer and an annular polyimide film. The invention further provides a preparation method for the large-current low-forward-voltage-drop silicon carbide Schottly diode chip. The preparation method is capable of, through using a parallel design of a PN junction and a Schottly junction, double-layer epitaxial growth, and ion implantation and nitrogen ion doping, generating a large implantation effect in a large current by using a Schottly metal Pt, reducing the electrical resistivity of the epitaxial layer, realizing the manufacture for the large-current low-forward-voltage-drop silicon carbide Schottly diode, thereby overcoming the defects in the prior art that the forward voltage drop of a device is reduced as well as the reverse leakagecurrent of the device is increased while a low barrier metal is selected and a chip area is increased, a rate of finished products is reduced, and the manufacturing cost is increased.

Description

technical field [0001] The invention relates to the technical field of semiconductor devices, in particular to a silicon carbide schottky diode chip with high current and low forward voltage drop and a preparation method thereof. Background technique [0002] Silicon carbide Schottky diodes based on wide-bandgap semiconductor materials make up for the shortcomings of silicon Schottky diode devices. Its critical breakdown electric field strength 10 times that of silicon materials ensures that it can work at higher reverse voltages, and at the same time SiC Schottky diodes have lower on-resistance, fast switching characteristics and high-temperature operating characteristics, making them ideal devices for high-voltage fast, high-temperature resistance and low power consumption. Silicon carbide Schottky diodes can provide nearly ideal dynamic performance. There is no charge storage during operation, and the reverse recovery current is only caused by its depletion layer junction...

AI Technical Summary

Problems solved by technology

[0003] In traditional technology, Schottky diodes choose low barrier metals and increase the barrier area to reduce forward voltage drop, but using low barrier metals and increasing the barrier area will increase the leakage current of Schottky diodes and reduce the device junction temperature ;Increase the layout size in the manufacturing process, the larger the size of a single chip, the greater the probability of defects, which is not conducive to the improvement of cost rate, and affects the reliability and consistency of the device; increasing the layout area of ​​a single chip reduces the The number of cores out of the wafer increases the cost of the device

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