Method for manufacturing ohmic contact on SiC matrix for preventing transverse spreading of metal

Abstract

The invention discloses a method for manufacturing ohmic contact on an SiC matrix for preventing transverse spreading of metal, which is characterized by consisting of the following steps of: dry-etching the SiC matrix, dividing a region for ohmic contact, depositing a metal layer in the region, and carrying out high-temperature annealing to form the ohmic contact, wherein before the step of depositing the metal layer, the following steps are added : (1) an oxidization step for oxidizing the SiC matrix to form an oxide layer with thickness of not less than 1000 angstroms; (2) and a step of removing the oxide layer on the region of the ohmic contact. By adopting the invention, the certain transverse spreading of the molten metal layer is effectively prevented in the high-temperature annealing process; a ohmic electrode is manufactured conveniently according to the design requirements; parasitical parameters are reduced and the performance of the SiC device or the circuit is improved.

Description

technical field [0001] The invention belongs to the technical field of making electrodes on semiconductor materials, and in particular relates to a method for preventing lateral expansion of metal layers when making ohmic contacts on SiC devices. Background technique [0002] SiC is a rapidly developing semiconductor material, known as the "third-generation semiconductor" after silicon and gallium arsenide, and has broad prospects in the preparation of semiconductor devices. [0003] In order to effectively connect the SiC device to the outside, it is necessary to make a contact between the SiC device and the metal wiring. There are two types of contacts that are frequently used: ohmic contacts and rectifying contacts. In an ideal ohmic contact, the current varies linearly with the applied voltage. In order to transmit as much current as possible from the SiC device to the entire circuit, the ratio of the ohmic contact resistance to the entire device resistance must be sma...

AI Technical Summary

Problems solved by technology

Since the thermal expansion coefficients of the metal layer and the SiC substrate are different at high temperatures of 900°C to 1200°C, and the thermal expansion coefficient of the metal layer is relatively large, it will expand laterally during high-temperature annealing, which deviates from the design requirements and increases parasitic parameters, reducing the performance of SiC devices or circuits

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