Method for manufacturing low-temperature silicon carbide ohmic contact and metal structure

Abstract

The invention discloses a method for manufacturing a low-temperature silicon carbide ohmic contact, comprising the following steps of S1, preparing an N-type or P-type silicon carbide substrate, and preparing a region where an ohmic contact is required to be manufactured; S2, depositing layers of metal on the ohmic contact region to form a metal layer, wherein the metal layer includes, in order from bottom to top, a nickel thin film layer formed by evaporation, an amorphous silicon thin film layer formed by sputtering, and a titanium thin film layer formed by evaporation or sputtering, and wherein an atomic ratio of silicon in the nickel thin film layer to nickel in the amorphous silicon thin film layer is greater than 0.25 but less than or equal to 0.50; and S3, annealing the metal layerat an annealing temperature of 600 to 780 degrees centigrade to prepare the ohmic contact structure. The method not only reduces the ohmic contact annealing temperature, but also prevents carbon deposition.

Description

technical field [0001] The invention relates to the field of semiconductor device manufacturing, in particular to a method for preparing a low-temperature silicon carbide ohmic contact and a metal structure. Background technique [0002] As a wide bandgap semiconductor material, silicon carbide (SiC) has attracted more and more attention due to its advantages such as high critical breakdown field strength, low on-resistance, high electron mobility and high thermal conductivity, especially in the power device market, and the application of SiC devices The prospects are very bright. [0003] In the manufacturing process of SiC power devices, the fabrication of electrodes is different from the traditional silicon process due to the high metal-semiconductor barrier, pinning effect, and complex surface states. It has always been the focus and difficulty of the SiC process. For the production of N-type silicon carbide ohmic contacts, it has become common knowledge in the industry...

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Problems solved by technology

In this regard, a large number of solutions to the problem of carbon precipitation have been proposed at home and abroad. The most common method is to deposit a protective layer on the ohmic metal, such as using TiN, TiW, Ti / Ni, NiSi, Ti / Pt, W or TaSi 2 / Pt and its derivative thin layers are used as ohmic metal protective layers to prevent carbon precipitation during annealing. However, these methods all have the problem of patterning the protective layer when patterned ohmic contacts are required. In addition, the annealing temperature is generally high

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