Panasonic Develops Insulated-Gate GaN Power Transistor
Low-loss and high-speed switching accelerates the miniaturisation of equipment, and expands the GaN power transistor market
Panasonic has developed an insulated-gate GaN power transistor capable of continuous stable operation with no variation in its threshold voltage.
According to the company, this technology makes it possible to further increase the speed of GaN power transistors, enabling the miniaturisation of various electronic equipment.
Metal Insulator Semiconductor (MIS) type GaN power transistors are expected to be practical for next-generation power devices. Panasonic has been researching MIS gate structure as a future technology to further increase its operation speed. However, hysteresis occurs in conventional MIS type GaN power transistors, and high-speed switching operations with a high current and a high voltage had not yet been confirmed.
Now, the company has confirmed the continuous stable operation of MIS type GaN power transistors — which are required for future ultrafast GaN power devices — at a current of 20 A. With a significant increase in switching frequency, the miniaturisation of peripheral passive components becomes possible, says Panasonic, helping to reduce the size of power supplies for servers and base stations.
Panasonic's newly developed GaN power transistors have continuous stable operation at a maximum gate voltage of +10 V. They also operate at high current and voltages (drain current of 20 A and breakdown voltage of 730 V). High-speed switching features an OFF operation time of 1.9 ns and ON operation time of 4.1 ns.
Use of AlON gate insulator
The use of aluminum oxynitride (AlON) and the improvement of the insulator formation processes reduces electron traps within the insulator. This results in the stable threshold voltage, which enables continuous switching operation. By suppressing the hysteresis at gate voltages up to +10 V, the stable operation of power conversion equipment with Panasonic's MIS type GaN power transistors is expected to be realised.
Damage-free recessed gate structure
When introducing the recessed gate structure necessary for high-current operation, suppressing processing damages under the gate electrode was an issue. In this development, it was possible to suppress such processing damages by forming the outermost layer at high temperature following the formation of the recess. As a result, normally-off operation as well as the suppression of hysteresis was achieved.
Advanced GaN on Si technologies
Panasonic has been already mass-producing GaN power transistors called GIT. This new MIS type GaN power transistor was developed as a future technology to achieve higher-speed operation. By applying the fabrication process technologies acquired through the mass production of GITs on silicon (Si) substrates, high current as well as high breakdown voltage was achieved.