Electronics and Information Engineering Laboratories

Advanced Electron Devices Laboratory

Basic Information


Naotaka Iwata


Research and development of small-sized, ultra-high speed devices for energy conservation society

Electronic products indispensable to life are composed of semiconductor devices, and the devices are becoming increasingly difficult in high integration, power-saving and high speed operation. To overcome this, Advanced Electron Devices Laboratory investigates semiconductor materials, devices and application technologies

Research Themes

Compound semiconductor heterojunction power devices
Compound semiconductor sensors with new functionality
Ultra-low energy consumption semiconductor devices and systems


Development of low-cost high-functionality semiconductor devices that operate with high efficiency for the energy conservation society

Research background

Today's society cannot stand without electronic devices made up of semiconductor devices. In order to realize a sustainable energy-saving society, there is a demand for power control devices that operate at low cost and with high efficiency. In Advanced Electron Devices Laboratory, we are researching devices with new functions centered on heterojunction power transistors using gallium nitride (GaN), and developing their fabrication processes and applied technologies for ultra-low power consumption systems.

AlGaN/GaN high electron mobility transistor (HEMT) on GaN substrate under test (left: transparent!), HEMT with side-gate (center) and drain current (ID) performances against side-gate voltage (VSG) for thicknesses of channel and C-doped buffer layers (right)

Research on compound semiconductor heterojunction power devices

We are conducting research on high electron mobility transistors (HEMTs) and vertical transistors using GaN. In HEMT research, we are evaluating the buffer layer provided on the GaN substrate and developing the fabrication process with the aim of realizing the device characteristics expected from the physical characteristics of GaN. In order to realize a vertical transistor that is more suitable for power control applications, it is essential to form a high-concentration p-type GaN region, and we are proceeding with research on acceptor impurity activation by laser irradiation.

Laser irradiation system for acceptor activation of Mg-doped GaN and resulted hole concentration against laser intensity

Research on ultra-low power consumption semiconductor devices and systems

For wireless power transfer and energy harvesting, there is a demand for high-performance devices that rectify from low voltage to high voltage with high efficiency. Current technology requires a large number of semiconductor devices, including control ICs. Advanced Electron Devices Laboratory is conducting research on a novel heterojunction diode that exhibits a low on-voltage using the results of the p-type GaN gate HEMT, and is developing a bridge circuit IC using this diode.


p-GaN gated anode diode (left), diode bridge & testing circuit (center) and full-wave rectification with input signal of 1.5 V and 0.18 V (right)

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