Fujitsu boosts gallium nitride power output three times

    To increase the radar observation area, it is necessary to increase the output power of the transistors used in its amplifiers. But in this case, the supply of high voltage can damage the crystals that form the transistor. Fujitsu scientists have developed a crystal structure that increases the current and voltage of a GaN nitride-transistor with a high electron mobility transistor (HEMT), increasing the output power of the transistors used in microwave transmitters by three times. More about the development of new technology, we will tell in the article.

    GaN HEMT technology can be used as a power amplifier for equipment such as meteorological radars - according to scientists' forecasts, this will increase the radar observation area by a factor of 2.3 for early detection of thunderstorm clouds, which create heavy showers. Fujitsu achieved the world's highest transistor density at 19.9 watts per millimeter of GaN HEMT transistor gate width using a protective layer based on indium, aluminum and gallium nitride (InAlGaN).

    Applications GaN HEMT

    In recent years, GaN HEMT transistors have been widely used as high-frequency power amplifiers in radars and wireless communication systems. They are also expected to be used in meteorological radars for accurate detection of local precipitation, as well as in millimeter wireless communication systems for fifth-generation mobile networks (5G). The range of microwaves compared to millimeter waves, which are used in radars and wireless communication systems, can be increased by increasing the output power of high-frequency amplifiers created on the basis of GaN HEMT transistors.

    Fujitsu has been researching GaN HEMT transistors since the early 2000s and is currently offering AlGaN HEMT transistors. They will become the new generation of GaN HEMT type transistors, which provide high-voltage operation through the use of high-density electrons.

    What does the new technology offer?

    In traditional InAlGaN HEMT transistors, the voltage between the gate and the drain electrodes fell on the electron supply layer, and a large number of electrons with high kinetic energy are created there. As a result, these electrons damaged the crystal structure of the layer. As a result, the transistors were limited to the maximum operating voltage.

    The mechanism of damage to the crystals and the new crystal structure.

    By using the new AlGaN separation layer, the voltage in the transistor can be distributed over the electron supply layer and the separation layer. By reducing the voltage concentration, the growth of the kinetic energy of electrons in the crystal structure is suppressed, and damage to the electron supply layer does not occur, which allows increasing the operating voltage to 100 V.

    New structure of GaN HEMT transistors and comparison of the output power of the new and traditional technology

    Future plans

    The heat generated in the transistor can be efficiently removed through the diamond substrate, the connection technology of which Fujitsu developed in 2017. When the GaN HEMT transistors with a crystal structure were tested during real tests, they demonstrated an output power of 19.9 W per millimeter of gate width, which is 3 times the output power of traditional AlGaN / GaN HEMT transistors.

    Detailed information on the new development was presented at the International Symposium on Growth of III-Nitrides event (ISGN-7), an international conference which was held from August 5 to 10 in Warsaw, Poland. Fujitsu is evaluating the heat resistance and power characteristics of GaN HEMT transistor power amplifiers using this technology to commercially manufacture amplifiers for applications such as radar and wireless systems based on 5G networks by 2020 fiscal year.


    1. Gallium nitride (GaN) is a semiconductor material with a higher breakdown voltage compared to traditional semiconductor materials, including silicon (Si) and gallium arsenide (GaAs).
    2. Transistors with high mobility of electrons (High Electron Mobility Transistor, HEMT) - a channel transistor, which operates on a layer of electrons at the boundary between two different semiconductor materials. It has a higher operating speed compared to traditional semiconductors.

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