In September, Xidian University of Microelectronics College of Microelectronics Hao Yue and his academician team in the international authority of the top journal IEEE Transactions on Industrial Electronics (Industrial and Electronic Engineers Association of Electrical and Electronics Engineers) and IEEE Transactions on Power Electronics has reported on the team's international highest performance GaN microwave diode, 2.45GHz microwave rectifier module, 5.8GHz microwave rectifier module and its high efficiency microwave wireless energy transfer demonstration system.

High-power microwave diodes are the core components of microwave systems. The traditional semiconductor microwave diodes such as silicon and gallium arsenide have a maximum power of only a few hundred milliwatts, which seriously restricts the development of megawatt wireless energy transmission systems and microwave limiters of hundreds of kilowatts. Therefore, high power microwave diodes have become urgently needed to be solved. Core device. According to the physical properties of semiconductor materials, the wide bandgap semiconductor gallium nitride (GaN) heterostructure is the most ideal material for the development of high-power microwave diodes. The power frequency characteristic parameters (fcVB) are silicon, gallium arsenide, silicon carbide, respectively. 500 times, 50 times and 4 times. Therefore, GaN high power microwave diodes have become an international research hotspot in this field.

However, the development of GaN high-power microwave diodes is very difficult. On the one hand, because of the large band gap of GaN, it is difficult to obtain the key characteristics of devices such as low turn-on voltage, low leakage current, and high breakdown voltage. Gallium material has a high dislocation defect density, resulting in extremely poor device reliability. After many years of research, the team of Academician Hao Yue innovatively proposed a low-work function metal grooved anode Schottky device structure. First, the Schottky contact surface is parallel to the dislocation defect direction through the groove structure, avoiding the bit. The effect of the wrong defect on the performance and reliability of the diode; the second is that the side of the groove is a non-polar surface of gallium nitride, and the non-polar surface is used to form a Schottky contact, which can reduce the diode turn-on voltage by half, and combine low-power The use of a functional metal electrode reduces the diode turn-on voltage from 1.2V to 0.4V for conventional structures. Besides, the use of a low-k anode dielectric greatly reduces the parasitic capacitance of the anode, enabling high-frequency operation of the diode.

Compared to traditional semiconductor Si and GaAs diodes, the device achieves low turn-on voltage (<0.4 V), low series resistance (< 5 Ω), low parasitic capacitance (<0.5 pF), and device cutoff frequency of 124 GHz. The most breakthrough is that the diode achieves a reverse breakdown voltage of more than 150 V. The single-tube rectification power is close to 10 watts, which is more than an order of magnitude higher than that of Si and GaAs. With the GaN microwave diode, the team successfully implemented 2.45 GHz and 5.8 GHz microwave rectifier circuits and wireless energy transfer systems. At 2.45 GHz operating frequency with input power of 0.75 W and 7.2 W, the rectifier circuit achieves 79% and 50% rectification efficiency, respectively. (Related results are published in: Kui Dang, Jincheng Zhang*, Hong Zhou*, et al., IEEE Transaction on Industrial Electronics, 2019, DOI:10.1109/TIE.2019.2939968, SCI District Paper)

At the same time, the team further proposed an LPCVD passivation method that solves the current collapse effect at a higher frequency band of 5.8 GHz and achieves 71% and 50 at 5.8 GHz at input powers of 2 W and 6 W. % rectification efficiency. Compared with traditional Si and GaAs diodes, the single-tube rectification power of GaN diodes is increased by 10-50 times under the same operating frequency and rectification efficiency, which can meet the future demand for high-frequency, high-efficiency, high-power rectification technology. Based on the rectifier module, the microwave wireless energy transmission system of 2.45 GHz and 5.8 GHz was designed and built, and the high efficiency microwave wireless energy transmission at 2 m distance was successfully realized. (Related results are published in: Kui Dang, Jincheng Zhang*, Hong Zhou*, et al., IEEE Transactions on Power Electronics, 2019, 10.1109/TPEL.2019.2938769, SCI District Paper).

It is reported that IEEE Transactions on Industrial Electronics is an international top journal in the field of electronics and electrical. IEEE Transactions on Power Electronics is an international excellent journal in the field of electronics and electrical. It mainly reports on the latest research progress in the fields of information, control, electrical and industrial electronics. SCI District TOP Journal.