Seed crystal high-temperature bonding equipment for aluminum nitride crystal growth and method thereof

Abstract

The invention discloses seed crystal high-temperature bonding equipment for aluminum nitride crystal growth and a method thereof. The seed crystal high-temperature bonding equipment comprises seed crystals, a crucible, an aluminum nitride crystal growth furnace, mechanical polishing and chemical cleaning equipment and a special heating and pressurizing device, pretreating the surface of a crucible cover and the back of the seed crystal, and placing the seed crystal on the crucible cover placing the crucible cover on a sample table of a heating and pressurizing device; placing a sacrificial wafer with the unpolished surface on the front face of the seed crystal in advance, and pressurizing the crucible cover and the seed crystal; raising the temperature and keeping the temperature; slowly cooling, filling nitrogen into the heating chamber to normal pressure, and slowly unloading a pressure transmission device on the sacrificial wafer; carrying out high-temperature shaping on the bonded seed crystal and crucible cover in an aluminum nitride crystal growth furnace; and therefore, obtaining the well-bonded aluminum nitride seed crystal. According to the method, the growth quality of the aluminum nitride single crystal can be improved, the process is simple, and low-cost preparation of the aluminum nitride single crystal is facilitated.

Description

technical field [0001] This patent relates to semiconductor manufacturing devices and processes, specifically to a new method and equipment for high-temperature bonding of seed crystals used in aluminum nitride crystal growth. Background technique [0002] Aluminum nitride materials have been widely used in high-temperature, high-frequency, high-power and radiation-resistant devices because of their high thermal conductivity, high breakdown field strength and many other excellent properties. At present, the research on aluminum nitride single crystal materials It has become a research hotspot in the semiconductor field. Aluminum nitride single crystal is mainly prepared by physical vapor transport (PVT). The physical vapor transport method generally uses the difference between the insulation layer and the position of the crucible to set the bottom of the crucible required for growth to a high temperature zone, and the top to a low temperature. The raw material gas evaporate...

AI Technical Summary

Problems solved by technology

The main problems of the first category of technologies are: (1) AlN single crystal growth requires a high temperature above 2000 °C, and the commonly used commercial high-temperature binders basically do not have the ability to withstand such high temperatures, and the few binders that meet the requirements are extremely expensive And often restricted from import; (2) Carbon-based or ceramic high-temperature adhesives contain impurity elements, which often enter the crystal in the form of defects, affecting the quality and optical properties of the single crystal; (3) The existence of pores is difficult to avoid during the bonding and curing process , resulting in a small temperature gradient in the radial and axial directions, and the quality of the subsequent growth of the crystal deteriorates

However, if the second type of technology is adopted, part of the surface of the seed crystal will be lost at first. What is more serious is that due to the tolerance fit of the fixture and the difference in thermal expansion coefficient, it is difficult to make close contact between the seed crystal and the crucible cover at high temperature, and it is very easy to lose the surface of the crucible in the radial direction. A temperature gradient is formed in the axial direction, resulting in poor crystal quality and a decrease in the degree of single crystal

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