SiC Schottky power diode and preparation method thereof

Abstract

The invention discloses a SiC Schottky power diode. The SiC Schottky power diode comprises an N-type 4H-SiC substrate, a P-type 4H-SiC isolation layer and an N-type 4H-SiC epitaxial layer, wherein the thickness of the N-type 4H-SiC epitaxial layer is 4-6 [mu]m; an inverted trapezoidal anode groove and an isolation groove are engraved in the middle of the epitaxial layer, and the tops of two ends of the epitaxial layer avoid inwards to form an isolation region; the isolation region and the isolation groove are filled with an insulating medium to form a current dredging structure; and the epitaxial layer is provided with an N+ injection region and a P+ injection protection region. The SiC Schottky power diode comprises: a cathode ohmic contact metal layer covering the N+ injection region; a first passivation layer arranged on the P+ injection protection region; a second passivation layer arranged at the bottom of the anode groove; an anode Schottky contact metal layer covering part of the surface of the first passivation layer, the surface of the anode groove and the surface of the second passivation layer; and a third passivation layer covering the remaining surface of the first passivation layer and extending towards the metal layers on the two sides. According to the invention, the performance and yield of the Schottky power diode under high working voltage are improved.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, and in particular relates to a SiC Schottky power diode and a preparation method thereof. Background technique [0002] The common crystal types of SiC (silicon carbide) are 3C, 4H and 6H. Among them, 4H-SiC is the best choice for manufacturing power electronic power devices because of its good quality and low price. [0003] 4H-SiC Schottky power diodes are suitable for power systems such as rectification and inverters, and are one of the indispensable new power components in energy conversion systems for new industries such as electric vehicles, industrial control, and high-speed rail. With the continuous improvement of power capacity, the operating voltage and operating current of 4H-SiC Schottky power diodes will also be further increased. [0004] In the existing 4H-SiC power Schottky power diodes, in order to achieve higher operating voltage (greater than 3000V), most of them are a...

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Problems solved by technology

However, when the thickness of the epitaxial layer is greater than 20 μm, the SiC epitaxial process will greatly reduce the performance and yield of 4H-SiC Schottky power diodes, which will cause inconvenience to the commercialization of high-voltage power Schottky power diodes.

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