Laser stripping method using metallic passage beds to transfer GaN substrate

Abstract

The present invention relates to a laser lift-off method to transfer the GaN liner by using a metal transition layer, in particular to a method of bonding silicon and GaN by using the metal transition layer and transferring GaN on a sapphire liner to a Si liner by combining the laser lift-off technology; and provides a method for transferring the GaN liner by using the metal transition layer. The Si liner is sputtered with Ti and Au in sequence to form a silicon chip sputtered with Ti and Au; GaN on the sapphire liner is sputtered with Ni and Au in sequence to obtain a GaN chip sputtered with Ni and Au; the silicon chip and the GaN chip are jointed front to front and then put into a bonding machine under 100 to 200 DEG C. After pre-bonding, the temperature of the bonding machine is raised to 200 to 600 DEG C. Then, the bonding machine anneals and a GaN / metal / Si bonded chip forms. After that, the GaN / metal / Si bonded chip gets adhesively connected onto a glass piece and fixed on an electric-driven platform. Laser wave with 365nm above are to radiate the bonded piece from one side of the sapphire.

Description

Technical field [0001] The invention relates to a method for using a metal transition layer to bond silicon (Si) and gallium nitride (GaN), combined with laser lift-off technology to transfer GaN on a sapphire substrate to a Si substrate. Background technique [0002] Due to its continuously variable direct band gap, excellent optical and electrical properties, and excellent physical and chemical stability, GaN-based materials are used in the preparation of short-wavelength semiconductor optoelectronic devices and high-temperature, high-pressure, and high-frequency microelectronic devices. Wide range of applications. Due to the lack of natural GaN single crystals in nature, GaN is usually grown on heterogeneous substrates, such as sapphire and SiC. Because the lattice structure of sapphire is similar to GaN and the price is cheaper than SiC, it has become the preferred substrate (Duan Meng, Hao Yue. Research progress of GaN-based blue LEDs[J]. Journal of Xidian University, 2003, ...

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Problems solved by technology

However, sapphire and GaN have a 16% lattice mismatch, resulting in high-density line dislocations in the epitaxial wafer structure, thereby limiting the quality and thickness of the GaN epitaxial layer (1, Plano W E, MajorJ S, Welch D F.X-ray studies of high quality GaN grown on 0001 sapphire[J]. Electronics Letters, 1994, 30: 2079-2081; 2. Shen X Q, Matsuhata H, Okumura H. Reduction of the threading dislocation density in GaN films grown on victim sapphire (0001) substrates [J].Appl.Phys.Lett., 2005, 86:021912-021914); In addition, Al 2 o 3 The thermal conductivity is poor, and the thermal conductivity is about 0.5W / cm K, which makes the heat dissipation problem of GaN-based devices prominent, especially in high-power devices and LDs; at the same time, Al 2 o 3 The electrical conductivity is not good, and the resistivity is greater than 10 at room temperature. 11 Ω·cm, which makes the vertical structure of the upper and lower electrodes used in ordinary LEDs no longer applicable to GaN-based LEDs. It is necessary to use a mesa electrode structure with p and n electrodes on the same side. The device manufacturing process is complicated, which affects the current diffusion and output of the device. Characteristics such as optical power (Wang Ting, Guo Xia, Fang Yuan, etc. Research on the structure and optical properties of GaN / metal / Si prepared by laser lift-off technology [J]. Functional Materials, 2007, 38(1): 88-90.)

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