[21p-E301-1~7] 13.7 Compound and power electron devices and process technology

[21p-E301-3] Positive Threshold Voltage Shift by Insertion of (AlGa)₂O₃ Back Barrier in Ga₂O₃ MOSFET

〇Takafumi Kamimura¹, Yoshiaki Nakata¹, Masataka Higashiwaki¹ (1.NICT)

Keywords:Gallium Oxide, Ion implantation doping, Back barrier

A fundamental drawback of the ion implantation process is the inability to form abrupt doping profiles since the Gaussian-like depth distribution of implanted dopants leads to a tail region beyond the designed doping region, as a result of which lateral Ga₂O₃ metal-oxide-semiconductor field-effect transistors (MOSFETs) with a Si-ion-implanted channel layer often showed deep-pinchoff characteristics with a threshold gate voltage (V_th) of smaller than -20 V. To develop highly-scaled MOSFETs, an improvement of the deep pinchoff is necessary because the short-channel effect, which manifests as a high output conductance, is expected to further shift the Vth to the negative side and degrade some of the device characteristics. In this work, by employing an (AlGa)₂O₃ back barrier, we succeeded in shifting the V_th of Ga₂O₃ MOSFETs with a Si-ion-implanted channel toward the positive side.