New Method Makes the Preparation Cost of Cubic Boron Nitride Reduced

Jay Narayan from North Carolina State University (NCSU) led his research team into finding a new method that can make h-BN (hexagonal boron nitride) changed into c-BN (cubic boron nitride), which is time-consuming and has low cost. It is expected to achieve the wide application of c-BN materials in high power electronic devices, transistors, solid state devices, etc.

There are four basic forms about boron nitride(BN). And the structure properties of h-BN and c-BN are similar to diamond and graphite. They are attractive in the field of electronic equipment and other applications. C-BN has good thermodynamic properties that are similar to diamond, suitable for integrated circuit. In addition, the high frequency power capacity is equivalent to that of silicon.

The new method can help to produce a kind of new material called Q–BN, in addition to being able to generate c-BN in the traditional sense. This new material needs to go through heating BN to high temperature and then make rapid cooling. It is worth mentioning that this team previously discovered a new carbon phase, and named it Q-carbon. The results were published in the Journal of Applied Physics last year.

"This research is another new progress after finding Q-carbon." Narayan said at news conference "By controlling the time and making full use of dynamic knowledge, we have already gone beyond the so-called BN thermodynamic limit, and found this new phase Q-BN."

This results are published in APL Materials. Narayan and his team use BN layer with the thickness of 500-1000nm and good thermodynamic stability to synthesize Q-BN and c-BN. Traditionally, the transformation from h-BN into c-BN needs to be under 9500 atmospheric pressure, to heat h-BN to 3500K  (3225 ℃). By contrast, Narayan and his team use the new method whose advantage is obvious.

In terms of electronic equipment, the performance of c-BN is better than diamond. For example, the energy band of c-BN is higher than diamond, which is more advantageous to high power electronic devices. There is no doubt that such quick and cheap c-BN synthesis method will give full play to the excellent properties of c-BN.

"The single crystal layer area is larger by using c-BN synthesis method. After the doping of n-type and p-type, it can produce high-power transistors and converter." Narayan said in an e-mail interview, "Larger converter will be replaced, and we finally will realize new smart grid that super power highway needs."