hBN Crucible Enables High-Quality AlN Single Crystal Growth

  Aluminum Nitride (AlN) is a wide-bandgap semiconductor material with excellent thermal conductivity, high breakdown voltage, and good electrical insulation properties. It has a wide range of applications in electronics, optoelectronics, and power devices. However, the growth of high-quality AlN single crystals is still a challenge due to the lack of suitable substrates and growth techniques.

 A recent study has reported a novel method for the growth of AlN single crystals using hot-pressed BN (HPBN, or hBN) crucibles by sublimation. The researchers found that free nucleation of AlN single crystals can be achieved in the HPBN crucibles without the need for any foreign catalysts or seeding materials. The as-grown AlN single crystals exhibited high crystal quality with low dislocation density and high optical transparency.

 The study was conducted by a team of researchers from Nagoya University, Japan, and was published in the journal Applied Physics Letters. The researchers used HPBN crucibles with different dimensions and orientations to investigate the growth behavior of AlN single crystals. They found that the growth rate of AlN single crystals was strongly dependent on the crucible size and orientation. The largest AlN single crystal grown in this study had a diameter of 10 mm and a height of 2 mm.

 The AlN single crystals grown by this method have great potential for various applications, such as high-power and high-frequency electronic devices, UV light-emitting diodes, and deep UV photodetectors. The high thermal conductivity and low thermal expansion coefficient of AlN make it an ideal material for high-temperature applications, such as power electronics and aerospace industries.

The choice of HPBN as a crucible for AlN crystal growth is due to several reasons. First, HPBN is a ceramic material made by hot-pressing boron nitride powder at high temperature and pressure. HPBN has excellent thermal stability, chemical inertness, and low impurity content, which can ensure the high purity and quality of the as-grown AlN single crystals. In contrast, conventional crucibles made of platinum or other metals can introduce impurities and cause contamination during crystal growth.

Second, HPBN has a high thermal conductivity and low thermal expansion coefficient, which can provide efficient heat transfer and reduce thermal stress during crystal growth. This is particularly important for AlN crystal growth, as AlN has a high thermal conductivity and low thermal expansion coefficient. The use of HPBN crucibles can also reduce the risk of thermal cracking and improve the crystal quality.

Third, HPBN crucibles are easy to manufacture and can be produced in different sizes and shapes to meet the specific needs of AlN crystal growth. QS Advanced Materials Inc. is one of the main suppliers of HPBN crucibles, offering a wide range of sizes and grades to meet the customers' demands. The largest HPBN crucible provided by QS Advanced Materials Inc. can reach up to 16x16x8 inches in size, which is suitable for large-scale AlN crystal growth. In conclusion, the free nucleation of AlN single crystals in HPBN crucibles by sublimation is a promising technique for the growth of high-quality AlN single crystals with various applications. QS Advanced Materials Inc. is one of the main suppliers of HPBN crucibles, offering a wide range of sizes and grades to meet the customers' demands. The development of this new growth method can lead to the commercial production of high-quality AlN single crystals for various industrial applications.

Reference

B. Liua, J.H. Edgar（Ed.）,Free nucleation of aluminum nitride single crystals in HPBN crucible by sublimation, Materials Science and Engineering B 117 (2005) 99–104