Silicon carbide junction barrier schottky diode and preparation method thereof

Abstract

The invention discloses a silicon carbide junction barrier schottky diode and a preparation method thereof. The silicon carbide junction barrier schottky diode comprises a cathode electrode, a siliconcarbide substrate, a first drift layer and a second drift layer which are arranged in turn from the bottom to the top and first field limiting rings, second field limiting rings, a passivation layerand an anode electrode. The depth of the first field limiting rings is less than that of the first drift layer and the first field limiting rings are distributed in the first drift layer in a spaced way and leveled with the upper surface of the first drift layer. The width of the second field limiting rings is less than that of the first field limiting rings and the depth is the same as that of the second drift layer and the second field limiting rings are distributed in the second drift layer in a spaced way. The first field limiting rings and the second field limiting rings are identical innumber and correspondingly in the inverted T-shape or n L-shape distribution. The anode electrode is located on the main junction, and the passivation layer is located on both sides of the anode electrode. The breakdown voltage of the schottky diode is increased and the difficulty of the preparation process is reduced.

Description

technical field [0001] The invention belongs to the technical field of semiconductor devices, and more specifically relates to a silicon carbide junction barrier Schottky diode and a preparation method thereof. Background technique [0002] Since silicon carbide has a wider band gap, higher thermal conductivity, higher electron saturation rate and higher critical breakdown electric field than silicon, the devices made of it can withstand harsh conditions such as high temperature and high pressure. , make up for the shortage of traditional silicon materials, and have broad application prospects in power devices. [0003] As the earliest commercialized diode, silicon carbide Schottky diode is not affected by the charge storage effect, has fast switching speed and low on-resistance, but is significantly affected by the barrier lowering effect under high voltage conditions, which limits Its application in the high-voltage field; compared with the Schottky diode, the PiN diode h...

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Problems solved by technology

[0006] Aiming at the defects of the prior art, the object of the present invention is to provide a silicon carbide junction barrier Schottky diode and its preparation method, aiming to solve the problems of the existing silicon carbide junction barrier Schottky diode due to the shallow depth of the field limiting ring. , so that the position of the peak electric field is close to the interface between the drift layer and the passivation layer, and the protection effect on the interface is weak, leading to the problem of early breakdown of the device

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