【Member News】Academician Hao Yue: Power Density and Irradiation are the Two Major Challenges of Nitride Semiconductor

    On April 20th, the opening conference of "2023 China Optical Valley Jiufeng Mountain Forum and Compound Semiconductor Industry Conference" was held in Wuhan Optical Valley. In the keynote report in the morning, Hao Yue, academician of Chinese Academy of Sciences and professor of Xidian University, delivered a speech, introducing the progress and challenges of compound semiconductor devices.

    Academician Hao Yue has long been engaged in scientific research and talent training of new wide-band gap semiconductor materials and devices, micro and nano semiconductor devices and highly reliable integrated circuits. He has made comprehensive innovative achievements in the functional materials and microwave devices of the third generation (wide band) semiconductor, the research and promotion of semiconductor short-wavelength photoelectric materials and devices, and the reliability and failure mechanism of micro and nano CMOS devices.

    At the conference, Academician Hao Yue introduced the research progress of gallium semiconductor materials such as nitride, and also reported the breakthrough achievements of his research team in gallium nitride and other materials.

    Academician Hao Yue pointed out that the greatest advantage of nitrogen is that it is only one among the current wide band semiconductor that can do two-dimensional electronic gas material, and that it can be completely on polarization to constantly adjust the density of two-dimensional electronic gas. Any kind of device can be made by adjusting the material and thickness of the barrier layer, which is one of its very good characteristics.

    The research team led by Academician Hao Yue has been conducting continuous research on gallium nitride materials for many years, and has made a series of breakthroughs in the technical directions of high power density gallium nitride millimeter-wave power devices, key technology of low-damage gallium nitride enhanced RF devices, low-voltage and high-efficiency gallium nitride RF power devices, and ultra-high frequency gallium nitride devices.

    For example, the 70nm gate long gallium nitride uHF device is for the first time in the world to use 100nm process to achieve fT> 100GHz on AlGaN, whose fT / fmax is 211 / 379GHz, which is the highest frequency in the world; the millimeter wave THz GaN SBD RF device has won the National 13th Five-Year Science and Technology Achievement Award, whose opening voltage of the device is only 0.4V, which greatly reduces the loss of diode.

    Among them, based on the 70nm gate long gallium nitride uHF device, the power additional efficiency of 55% in the k-band is realized, far exceeding the performance of the gallium arsenide device in this respect. These excellent characteristics of nitride make it promising in future 6G communication.

    When talking about the future research challenges of nitride semiconductor, Academician Hao Yue believes that, like silicon carbide, nitride semiconductor also faces many challenges, the first of which is how high its power density can reach; the second of which is the problem of space irradiation.

    Academician Hao Yue pointed out that there will be irradiation problems not only in space applications, but also in current aircraft. If this problem cannot be solved, it will be difficult for efficient power devices to be used in the aerospace field.

    In addition to nitride, oxide semiconductors have also attracted great attention of the industry in recent years. In Academician Hao Yue's opinion, although oxide semiconductor still has a certain distance from industrial application, but has been seen the prospect. Oxide semiconductors have a wider bandwidth and can achieve lower losses than gallium nitride and silicon carbide. But oxides also have weaknesses, that is, the problem of heat dissipation. With it unsolved, it is impossible to achieve industrialization.

    At present, Shanghai Institute of Microsystem and information Technology and Xidian University used Smart Cut to transfer wafer grade gallium oxide film to the high thermal conductivity substrate, which partially solved the problem of low thermal conductivity of gallium oxide substrate and realized the transfer of 4-inch gallium oxide material.

    At the end of his speech, Academician Hao Yue pointed out that the road of heterogeneous and heterogeneous integration should be taken in the future, and compound semiconductors should be closely integrated with silicon semiconductors. He, in turn, called for the domestic should set up an open platform, realize silicon integrated circuit and compound semiconductor multi-function integration. Therefore, whether optoelectronics or sensors, or power electronics, can be widely integrated with silicon integrated circuit, to realize the real sense of multi-function, and promote the development of the whole electronic information industry in our country.