Preparation method of deep sub-wavelength periodic stripe structure on surface of wide bandgap semiconductor

Abstract

The invention discloses a preparation method of deep sub-wavelength periodic stripes on the surface of a wide bandgap semiconductor. Femtosecond laser processing is assisted in forming the deep sub-wavelength periodic stripe structure in an irradiation area in a manner of pre-plating a metal film on the surface of a wide bandgap semiconductor material. By utilization of the metal/wide bandgap semiconductor composite structure, in the femtosecond laser irradiation process, absorption of the material to incident light energy can be greatly enhanced, and the interaction efficiency of femtosecondlaser and the wide bandgap material is improved. According to the method, the effect of reducing an ablation threshold of the material is obvious, and the formed deep sub-wavelength stripe period is fine. The method also has the advantages of simple process, wide applicability, strong flexibility and the like. Deep sub-wavelength stripes with different shapes and different space periods on the wide bandgap semiconductor can be realized by designing femtosecond laser energy flow, pulse number and processing area patterns.

Description

technical field [0001] The invention relates to the field of material processing, in particular to a method for preparing a deep sub-wavelength periodic stripe structure on the surface of a wide-bandgap semiconductor by laser processing, and belongs to the technical field of femtosecond laser micro-nano processing. Background technique [0002] Wide bandgap semiconductors represented by silicon carbide (3.26eV), gallium nitride (3.4eV), zinc oxide (3.37eV), etc. are called third-generation semiconductors. Compared with the first-generation (Si / Ge) and second-generation semiconductors (gallium arsenide (GaAs), indium antimonide (InSb)) materials, the third-generation semiconductors have a wide band gap and a high breakdown electric field. High thermal conductivity, high electron saturation rate and higher radiation resistance, suitable for high temperature, high frequency, radiation resistance and high power devices. In addition, due to the high luminous efficiency and high ...

AI Technical Summary

Problems solved by technology

However, due to the wide bandgap of wide-bandgap semiconductors and their transparency to visible and near-infrared light, their absorption of femtosecond lasers is limited by multi-photon ionization and tunnel ionization, and the ablation threshold is usually higher than that of metals and semiconductors.

Under high-energy flow, the ablation of the material surface is severe, and the laser-induced periodic stripe structure morphology is difficult to control

In addition, the laser-induced stripe period greatly depends on the laser fluence and decreases as the fluence decreases. If the ablation threshold fluence cannot be further reduced, it will be difficult to form a finer deep subwavelength stripe structure

[0004] This laser processing problem caused by the nature of the material itself has brought great difficulties to the processing and application of wide bandgap semiconductors.

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