High mobility field effect transistor based on BaSnO3 with Al2O3 gate oxide

We fabricated an n-type accumulation-mode field effect transistor based on BaSnO3 transparent perovskite semiconductor, taking advantage of its high mobility and oxygen stability. We used the conventional metal-insulator-semiconductor structures: (In,Sn)2O3 as the source, drain, and gate electrodes, Al2O3 as the gate insulator, and La-doped BaSnO3 as the semiconducting channel. The Al2O3 gate oxide was deposited by atomic layer deposition technique. At room temperature, we achieved the field effect mobility value of 17.8 cm2/Vs and the Ion/Ioff ratio value higher than 105 for VDS = 1 V. These values are higher than those previously reported on other perovskite oxides, in spite of the large density of threading dislocations in the BaSnO3 on SrTiO3 substrates. However, a relatively large subthreshold swing value was found, which we attribute to the large density of charge traps in the Al2O3 as well as the threading dislocations.