GaN-Based Enhancement-Mode Metal–Oxide–Semiconductor High-Electron Mobility Transistors Using LiNbO₃Ferroelectric Insulator on Gate-Recessed Structure

Abstract

To fabricate AlGaN/gallium nitride (GaN) enhancement-mode metal-oxide-semiconductor high-electron mobility transistors (E-MOSHEMTs), the gate-recessed structure and the LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ferroelectric film were utilized in this paper. The LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ferroelectric films deposited on the photoelectrochemically etched gate-recessed regions of the AlGaN/GaN E-MOSHEMTs as the gate insulator using a pulsed laser deposition system. The polarization-induced charges of the 2-D electron gas resided on the interface between the AlGaN and GaN layers could be modulated by the C <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> domains of the crystalline (006) LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ferroelectric films annealed in an oxygen ambience at 600°C for 30 min. When the 15-nm-thick AlGaN was formed in the gate-recessed regions, the threshold voltage and the maximum transconductance of the resulting gate-recessed LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /AlGaN/GaN E-MOSHEMTs were +0.40 V and 56.0 mS/mm, respectively. Furthermore, the flicker noise was the dominant noise in the resulting E-MOSHEMTs. The associated normalized low-frequency noise power density of 8.1 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> Hz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> was measured.