CBN's new preparation process will open the next generation of smart grid

Professor Jay Narayan of the University of North Carolina (NCSU) led a team to develop a new preparation method for hexagonal boron nitride (h-BN)-converted cubic boron nitride (CBN). The conversion speed and preparation cost are faster than traditional processes. It is cheaper and is expected to be used in applications such as high-power electronic devices, transistors, and solid-state components.
There are four basic forms of boron nitride, of which h-BN and CBN are the two most widely used in the field of electronic devices, and their structures and properties are very similar to those of diamond and graphite. In terms of integrated circuit applications, CBN has very good thermal conductivity; its high frequency power performance is comparable to that of silicon.
This new preparation method of the NCSU team can produce both traditional cubic boron nitride and a new type of material called Q-BN, and 'Q' stands for "quenching" of this material. "Phase, heat it to a certain temperature and then cool it quickly. As early as 2015 in the Journal of Applied Physics, the team published a study on a new phase of Q-carbon, or carbon; the Q-BN development was based on this.
Professor Narayan said: "This is another technological achievement after Q-carbon R&D and Q-carbon conversion of diamonds. With power control and time control, we successfully bypassed the bottleneck of boron nitride thermal power technology and developed boron nitride. The new phase."

The study was published in the APL Materials Journal, and Narayan and his team used Q-BN and CBN to prepare h-BN layers with a thermal stability of 500-10000 nm. The h-BN layer was placed on a substrate and heated to 2530 ° C using a high power laser pulse. The substrate absorbed heat to complete the "quenching" of the h-BN layer. The entire experimental procedure was carried out at room temperature for only one-fifth of a microsecond (five millionths of a second).
The key to the experiment was the preparation of the substrate below the h-BN layer, which affected the cooling rate of the h-BN layer. By controlling the cooling process, it can be determined whether the product is a conventional CBN or a new Q-BN.
The biggest advantage of the new method for converting H-BN to CBN is the low cost, room temperature pressure operation, which requires relatively low temperature; while the conventional process requires increasing the temperature to 3225 ° C and the pressure up to 95,000 atmospheres.
The low-cost and fast preparation process makes CBN more convenient in the application research of electronic equipment, and its advantages may be greater than diamond. For example, CBN has a higher bandgap than diamond and is advantageous in high power component applications.
Narayan added: Now, we can use CBN to prepare large-area single-crystal films, and also perform n-type and p-type dopant plating for high-power transistors and transfer switches. These technologies can replace bulky transformers and build next-generation power grids for super-electric highways.