Epi-Gd₂O₃-MOSHEMT: A Potential Solution Toward Leveraging the Application of /Si AlGaN/GaNHEMT With Improved ION/IOFF Operating at 473 K

In this article, we report the temperature-dependent transistor characteristic of Epi-Gd₂O₃/AlGaN/GaN metal oxide semiconductor high electron mobility transistor (MOSHEMT) and compare its properties with that of AlGaN/GaN metal-Schottky high electron mobility transistor (HEMT) grown on 150 mm Si (111) substrate. Introducing an epitaxial single crystalline Gd₂O₃ between the metal gate and AlGaN barrier not only improves the gate leakage current significantly but also enhances its thermal stability. We observe that there is no significant change in the gate leakage current even at 473 K compared to that measured at room temperature (RT) (298 K), and this is also evident in the transistor's subthreshold behavior at 473 K. We have determined the electric field within the Gd₂O₃ as well as AlGaN and investigated the leakage conduction mechanism through Gd₂O₃. The Ion/Ioff of the transistor was measured as high as ~10⁸ even at 473 K with the lowest VTH shift (91.4 mV) with temperature. Our measurements also confirm the presence of polar optical phonon scattering, which directly affects the 2-D electron gas (2DEG) mobility at high temperatures and thus the electrical characteristics of HEMT and MOSHEMT.