The application of GaN on diamond wafer substrate in satellite communication, national defense and military industr

At present, GaN-based devices have been widely used in optoelectronics, radio frequency and automotive fields. However, the high-frequency and high-power performance advantages of GaN-based power devices have not been fully utilized due to the junction heat problem in the active region. Traditional substrate and packaging heat dissipation technologies are difficult to solve the ' hot ' bottleneck problem. Diamond is a wide band gap semiconductor material with excellent performance. As a new type of thermal management material, it has ultra-high thermal conductivity. Therefore, it has great application potential in the heat dissipation of high frequency and high power GaN-based high electron mobility transistor ( HEMT ) and circuit, and can effectively reduce the self-heating effect of GaN-based high power devices.

At present, there are three manufacturing methods :

Figure 1

The combination of GaN and diamond makes full use of the ultra-high thermal conductivity of diamond, which is more effective and efficient in heat dissipation than other materials. In addition, the high breakdown field, high saturation velocity and excellent thermal properties of diamond are conducive to long-distance or high-power signal transmission, which makes GaN & diamond stand out in RF applications. Diamond with a unique combination of high thermal conductivity, mechanical strength, electrical insulation, low weight and chemical inertness provides better electrical equipment operation, lower operating temperature, higher reliability and longer service life for high-frequency active semiconductors. Therefore, it is considered to be an excellent material for high power density / high frequency equipment.

AkashSystems focuses on the development and supply of small satellites ( CubeSat ) as well as RF power amplifiers Recently demonstrated high-performance diamond-based GaN transistors ( simplified power amplifiers ). It exhibits a power added efficiency ( PAE ) of 60 % at the k-band 20 GHz frequency ( see Figure 2 ).

Figure 2 : The PAE of the sample device using a 2.9 W ( 5.6 W / mm ) HEMT with a gain of 7.9 dB is 61 %, and the bias point is 24 V.

Akash Systems uses ' gradient diamond with low thermal boundary resistance ( TBR ) ' to fabricate GaN on diamond ( green ). This curve shows a peak temperature of 152 ° C ( the first peak ). The temperature of SiC-based GaN at the same point on the device is 232 °C.

Fig.3 : The temperature distribution from channel center to channel edge of GaN 10finger HEMT wafer on different types of diamond is shown.

The above two experiments fully prove that diamond-based gallium nitride has sufficient superior characteristics to be applied in the fields of satellite communications and defense military industry.CSMH focuses on the research and production of diamond wafers. At present, it has diamond wafers, diamond heat sinks, GaN on diamond, AlN on diamond and other products. Among them, high-power semiconductor lasers packaged by diamond heat sinks have been used in optical communications. In the fields of laser diodes, power transistors, and electronic packaging materials, it can provide customers with diamond thermal management solutions.