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

In this article, we report the temperature-dependent transistor characteristic of Epi-Gd
₂
O
₃
/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 Gd
₂
O
₃
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 Gd
₂
O
₃
as well as AlGaN and investigated the leakage conduction mechanism through Gd
₂
O
₃
. The I
_ON
/I
_OFF
of the transistor was measured as high as ~10
⁸
even at 473 K with the lowest V
_TH
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.