Remarkable breakdown voltage enhancement in AlGaN channel high electron mobility transistors

The channel layer substitution of a wider bandgap AlGaN for a conventional GaN in high electron mobility transistors (HEMTs) is an effective method of enhancing the breakdown voltage. We demonstrated a remarkable breakdown voltage enhancement in these AlGaN channel HEMTs. The obtained maximum breakdown voltages were 463 and $1650\mathrm{V}$ in the ${\mathrm{Al}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{N}∕{\mathrm{Al}}_{0.38}{\mathrm{Ga}}_{0.62}\mathrm{N}$ HEMT with the gate-drain distances of 3 and $10\mu \mathrm{m}$ , respectively. This result is very promising for the further higher power operation of high-frequency HEMTs.