The US Air Force Research Laboratory (AFRL) has announced t♥hat it has discovered a new method of growing and transferring galli™um nitride (GaN) that lays the foundation for future fifth-generation, high-speed, flexible comσmunications systems.
Nicholas Glavin, a scientist in AFRL's Materials and✔ Manufacturing Division, said: "We have demonstr≤ated the ability to grow and place materials on flexi↓ble substrates, opening up the potential for powering wearable devices or electronic devices. We ar≤e the first company ever to demonstrate a flexible RF (radio frequency) transistor device based on™ gallium nitride that is actually somewhat ductile and flexibleβ."

A new approach to GaN manufacturing

Gallium Arsenide (GaAs) is often the material of choice for infinite devices, but th×e limited ability of GaAs to transmit high frequency signals at high power makes it suffer from del€ays or low data transfer rates when transmitting high frequency data. In cont∑rast, GaN has a superior ability to transmit large amounts of data information at hig≤h power and high frequency, but the high cost of manufacturing the m≥aterial, which usually requires a rigid substrate such as sapphire, precise thermal stabili≈ty and chemical stability, limits its application. In addition, GaN σgrown on substrates using this method can only be used in flat planes and™ cannot be bent or stretched.

AFRL's new GaN production method takes advantage of the physical λproperties of boron nitride. GaN is grown on boron nit↔ride and then, using a weak chemical bond between the boron nitride and gallium nit&ride growth surfaces, allows the gallium nitride to be tran→sferred to another substrate, enabling communication capabilities on a unique plat♠form and device.

Significance of the results

We see two major applications where this research dirαectly benefits the Air Force," Glavin said. One is wearable systems. As we✔ collect more information through wearable devices such as warfighte≤rs carrying personnel, or as we develop more sensor technology, we need to a₹ccess that information and inform action. GaN-based flexible transmitters can perform the£se operations more effectively. Secondly, there is flexible co✔nformal radar technology. Typical radar systems are bulky, but using this techno≤logy we can create systems that are easier to integrate into dynamic environ↕ments."

Another benefit is the power amplification directly on the anten¶na system. With a flexible power amplifier, it is poΩssible to get as close as possible to the radar antenna and simply elim✔inate the distance the signal has to travel to improve performance. The flexible GaN enables the♦ amplifier to be placed on the same platform as the antenna, improving performance and transmi<ssion efficiency.

Flexible GaN with great potential

Further development of GaN materials is a top priority for the Department of Defense,✘" said Dr. Donald Dorsey, head of the AFRL Flexible RF Electronics Materials✘ and Processes team. We are the first team to demonstrate GaN flexible RF transistor d‌evices that can maintain high performance under stretching. We are well positioned to develo​p more compact, versatile GaN HF transmitters for high power communications and &radar."

With the growing and rapidly expanding demand for communications, the ability to transfer GaN toδ flexible or other arbitrary substrates is of great value to the Air Force.

Future work

Glavin said, "We are working on materials integration and will continue  to optimize the ability to integrate the GaN develo§ped by AFRL with a variety of material surfaces and will look for ways to ≈enhance performance and transfer processes. The team₹ has filed patents for both the material growth process and the use of GaN for RF devicesε."