Silicon carbide diode and preparation method thereof

Abstract

The invention discloses a silicon carbide diode and a preparation method thereof. The silicon carbide diode comprises a silicon carbide substrate (11), a silicon carbide epitaxial layer (12), a patterned field plate dielectric layer (16b), a patterned Schottky contact electrode (17b) and an ohmic contact electrode layer (18). The silicon carbide epitaxial layer (12) is arranged on the front surface of the silicon carbide substrate (11). A patterned ion implantation region (15) is arranged in the silicon carbide epitaxial layer (12) and along the upper surface of the silicon carbide epitaxial layer (12). The upper surface of the silicon carbide epitaxial layer (12) is provided with the patterned field plate dielectric layer (16b), and a non-patterned region covered by the patterned field plate dielectric layer (16b) on the upper surface of the silicon carbide epitaxial layer (12) is provided with the patterned Schottky contact electrode (17b). Part of the region of the upper surface ofthe patterned field plate dielectric layer (16b) is covered by the patterned Schottky contact electrode (17b), and the remaining regions are exposed. The ohmic contact electrode layer (18) is arrangedon the back surface of the silicon carbide substrate (11).

Description

technical field [0001] The invention belongs to the technical field of semiconductor devices, and in particular relates to a silicon carbide diode and a preparation method thereof. Background technique [0002] Silicon carbide materials have the characteristics of wide band gap, high breakdown field strength, high thermal conductivity, high saturation electron mobility, and excellent physical and chemical stability, and are suitable for working in high temperature, high frequency, high power and extreme environments. Silicon carbide diodes include two types: unipolar devices and bipolar devices. Unipolar devices refer to devices that have only one carrier conduction in the working state, such as Schottky diodes and junction barrier Schottky Diode; a bipolar device refers to a device that has two types of carrier conduction in the working state, such as a PiN diode. The turn-on voltage of unipolar devices is small, but when high-voltage devices are prepared, the thickness of...

AI Technical Summary

Problems solved by technology

The turn-on voltage of unipolar devices is small, but when high-voltage devices are prepared, the thickness of the drift layer increases, resulting in increased on-state resistance and large on-state losses of the device; bipolar devices have a conductance modulation effect of minority carriers that can reduce on-state resistance , but due to the large self-built potential difference of the PN junction of silicon carbide, the turn-on voltage is as high as 3V, which also leads to a large on-state loss

[0003] In applications, the surge current and avalanche current tolerance of silicon carbide diodes need to be improved

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