Pulsed E-/D-Mode Switchable GaN HEMTs With a Ferroelectric AlScN Gate Dielectric
Jeong Yong Yang, S. Y. Oh, Min Jae Yeom, Seokgi Kim, Gyuhyung Lee, Kyusang Lee, Sungkyu Kim, Geonwook Yoo
Abstract
In this study, we demonstrate ferroelectric GaN high-electron mobility transistors (HEMTs) with a sputtered AlScN gate dielectric, exhibiting a large memory window of ~ 14.6 V and a high on/off ratio of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim ~10^{{8}}$ </tex-math></inline-formula> . The strong polarization of AlScN layer contributes to the remarkably large threshold voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\text {th}}{)}$ </tex-math></inline-formula> tuning range with counterclockwise hysteresis depending on voltage sweep ranges and pulsed parameters. Moreover, a recessed-gate structure enables the pulsed enhancement and depletion mode switching. The reconfigurable Vth via pulse modulation further allows feasibility of NOR logic gate with the single ferroelectric GaN HEMT.