Surface treatment method after laser lift-off of a nitride material

Abstract

The invention discloses a surface treatment method after nitride material laser lift-off. The surface treatment method comprises the following steps: preparing a nitride composite substrate or a nitride single crystal substrate in a laser lift-off manner; selecting a cavity, enabling the cavity to be filled with a volatile corrosive liquid, putting the nitride composite substrate or the nitride single crystal substrate above a liquid level in the cavity, sealing the cavity so that a closed cavity is formed, standing for a period of scheduled time T, and using an atmosphere generated by volatilization of the corrosive liquid to carry out corrosion treatment on the surface, after laser lift-off, of the nitride composite substrate or the nitride single crystal substrate; cleaning and drying the nitride composite substrate or the nitride single crystal substrate in the cavity to complete atmosphere corrosion treatment on the surface after laser lift-off. A nitride surface after lift-off is treated by using an atmosphere corrosion method, the impurities such as residual metals on the surface after lift-off are removed, the ingredients and roughness of the surface after lift-off are improved, and the later-period homoepitaxy effect and chip performance are improved.

Description

technical field [0001] The invention relates to a surface treatment method after laser stripping of a nitride material. Background technique [0002] Representative materials of the third-generation semiconductor nitride materials, especially GaN and AlN materials, are all wide-bandgap semiconductors with direct band gaps of 3.39ev and 6.3ev. Detectors and electronic power devices have broad market application prospects. [0003] Due to the complex and expensive preparation process of GaN single crystal, GaN-based light-emitting diodes are generally heteroepitaxial on sapphire substrates with similar crystal structure, but sapphire is insulating and has poor thermal conductivity, which affects the life of its LED chips and The luminous efficiency leads to uneven current distribution and serious heat dissipation problems, the hardness is difficult to cleavage, and the chip process is complicated, and the material utilization rate is low, which limits its application in high ...

AI Technical Summary

Problems solved by technology

[0004] Impurities such as metals remaining after the nitride semiconductor substrate is lifted off by laser and the rough surface caused by it will destroy the activity of the substrate surface in the preparation of thermal and conductive nitride composite substrates and single crystal substrates, increasing the difficulty of homoepitaxial growth. The leakage current of the device will be increased in the preparation of the structural device, which will affect the light extraction efficiency, performance and stability of the device. Therefore, it is necessary to perform corrosion treatment on the surface after laser lift-off

At present, there are two methods for surface treatment after laser lift-off in the market or scientific research institutions. 1) Heating and melting technology. The melting point of metal Ga is 29.8°C, and Ga metal can be melted and removed by heating, but heating has a negative effect on GaN epitaxial film and bonding. The combined dielectric layer has certain damage, which significantly increases the surface defects and crystal quality of the GaN thin film, and finally affects the device performance and stability. Moreover, this method is only applicable to the GaN surface after laser lift-off.

2) Hydrochloric acid immersion method, this method is suitable for surface treatment after stripping of AlN, GaN and other nitrides, this method uses hydrochloric acid immersion corrosion, then the substrate after stripping is placed in the liquid, that is, the substrate is completely immersed in the liquid, Ga, Ga, Active metals such as Al will react rapidly and violently, release a large amount of gas, and cause a very large impact on the surface of the stripped nitride, and the residual stress changes very rapidly. , AlN film cracks, or even cracks, damage the substrate surface and increase the difficulty of epitaxy, hindering the development and promotion of industrialization. In addition, hydrochloric acid immersion corrosion has a certain corrosive effect on the dielectric layer and the transfer substrate, which is easy to cause The debonding phenomenon seriously affects the stability of the bonding product and its device performance, increases the leakage current of the device and the stability of long-distance work

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