A kind of high-purity aluminum nitride powder and aluminum nitride powder purification method

Abstract

The invention relates to a high-purity aluminum nitride powder and a method for purifying the aluminum nitride powder. Use reducing gas to perform high-temperature gas washing treatment on the synthesis cavity where the mixed powder of Al powder and AlN powder is located, to remove the oxygen in the synthesis cavity; in a vacuum state, at the first purification temperature, remove the mixed Hydroxide in the powder impurities, at the second purification temperature, remove the carbon in the mixed powder impurities, and at the third purification temperature, use the Al steam to remove the aluminum oxide in the mixed powder impurities . The purification method is simple, through the rational design of the impurity removal sequence and the corresponding purification steps, and the addition of Al powder, the decomposition of AlN powder in the purification process is effectively suppressed, and the loss of raw materials is reduced. Through high-frequency combustion infrared absorption method and inert gas pulse Infrared thermal conductivity test shows that the carbon content of the aluminum nitride powder obtained in the present invention is 42PPM, the oxygen content is 220PPM, and the purity is high.

Description

technical field [0001] The invention relates to the preparation of aluminum nitride, in particular to a high-purity aluminum nitride powder and a method for purifying the aluminum nitride powder. Background technique [0002] Semiconductor materials and synthesis technology are the cornerstone of the development of modern information technology. In the 20th century, the first and second generation semiconductor materials represented by silicon (Si) and gallium arsenide (GaAs) promoted the rapid development of electronics and optoelectronic technology, and entered the 21st century. , with higher requirements for material performance, the third-generation semiconductor materials represented by aluminum nitride (AlN), silicon carbide (SiC), and gallium nitride (GaN) make up for the intrinsic properties of the first and second-generation materials Insufficient, has greatly promoted the development of the semiconductor industry. [0003] AlN has a direct band gap of 6.2eV, a wid...

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Problems solved by technology

[0009] At present, there are two main methods for synthesizing aluminum nitride, one is vapor phase physical transport (PVT), and the other is hydride vapor phase epitaxy (HVPE). According to different synthesis principles, the HVPE method has a low synthesis temperature but a slow growth rate. , suitable for thin film growth; the disadvantage of the PVT method is that the synthesis temperature is high, but the synthesis speed is fast, so this method is suitable for bulk crystal growth

The growth of crystals by PVT method is the process of sublimation and decomposition of AlN powder in the high temperature area and crystal growth in the low temperature area, and the carbon and oxygen impurity elements brought by the powder during the growth process affect the properties of the crystal, such as the UV transmittance and thermal conductivity. , high pressure resistance, etc., and even the accumulation of a large number of impurity elements will cause problems such as crystal cracking. In order to solve this problem, the raw material powder needs to be cleaned of impurities. The current method of powder cleaning is to put the powder into a high temperature resistant crucible Then, through high-temperature calcination, the impurities in the powder are eliminated. After the removal of impurities, the powder becomes irregular cylindrical and ceramicized or even crystallized. The cylindrical structure is not conducive to the removal of impurities inside the block, and the high hardness of ceramicization is in the later stage. The crushing and grinding process brings great difficulties, resulting in excessive loss of powder, and the use of mechanical crushing can easily cause secondary pollution of raw materials

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