Prof. Takuya Maeda’s research group in The University Tokyo and Mitsubishi Chemical Corporation have succeeded in demonstration of kV-class GaN photoconductive semiconductor switches (PCSS). In the study, Mn-doped semi-insulating GaN bulk substrates were used. To form ohmic contacts, n-type region was selectively formed by Si-ion implantation followed by high temperature activation annealing. Under above-bandgap ultraviolet illumination (on state), photocurrent was clearly observed. The GaN PCSSs with the same structure using Fe/C co-doped GaN substrates were also fabricated. In the Mn-doped GaN PCSSs, the photocurrent was approximately 40 times higher than that in the Fe/C co-doped GaN PCSSs. Under the dark condition (off state), the leakage current was very low, and the breakdown voltage of 2.4 kV was achieved for the GaN PCSS with the ohmic electrode distance of 75 μm. These results showcase the potential of a GaN PCSS using a Mn-doped semi-insulating GaN substrate, and contribute the realization of energy-efficient and electro-magnetic interference (EMI)-free power devices.
Measurement of photocurrent in GaN PCSS fabricated in this study.
Papers
Conference: The 38th International Symposium on Power Semiconductor Devices and ICs (ISPSD 2026)
Title: kV-Class GaN Photoconductive Semiconductor Switches Using Mn-Doped Semi-Insulating GaN Bulk Crystals
Authors: Takuya Maeda*, Chinwei Li, Ryosho Nakane, Kenji Iso
URL: https://www.ispsd2026.com
※Proceedings will be published in IEEE Xplore digital library in August 2026