Comparative studies on AlGaN/GaN/Si MOS-HFETs with Al₂O₃/TiO₂stacked dielectrics by using an ultrasonic spray pyrolysis deposition technique

Abstract

Al 0.26 Ga 0.74 N/GaN metal-oxide-semiconductor heterostructure field-effect transistors (MOS-HFETs) grown on a Si substrate with Al 2 O 3 /TiO 2 stacked gate dielectrics formed by using nonvacuum ultrasonic spray pyrolysis deposition (USPD) technique are investigated. High permittivity (k) values of Al 2 O 3 and TiO 2 were characterized to be 9 and 46.1, respectively, with an equal layer thickness of 10 nm. The present MOS-HFET (Schottky-gate HFET) design has demonstrated enhanced device characteristics at 300 K, including maximum drain-source current density (I DS,max ) of 725 (530) mA/mm, I DS at V GS =0 V (I DSS0 ) of 471 (383) mA/mm, gate-voltage swing (GVS) of 2.5 (1.6) V, two-terminal gate-drain breakdown voltage (BV GD ) of −182 (−121) V, turn-on voltage (V on ) of 4.9 (3.2) V, three-terminal off-state drain-source breakdown voltage (BV DS ) of 174 (103) V, on/off current ratio (I on /I off ) of 5.6×10 7 (3.7×10 3 ), unity-gain cut-off frequency ( f T ) of 10.3 (6.8) GHz, maximum oscillation frequency ( f max ) of 14.8 (8.6) GHz, and power-added efficiency (P.A.E.) of 38.5% (31.7%) at 2.4 GHz. High temperature device characteristics up to 450 K are also discussed.

Comparative Study on Graded-Barrier AlxGa1−xN/AlN/GaN/Si Metal-Oxide-Semiconductor Heterostructure Field-Effect Transistor by Using Ultrasonic Spray Pyrolysis Deposition Technique

“…The ohmic contacts were obtained by annealing the device at 900 °C by using the ULVAC MILA-5000 rapid thermal annealing (RTA) system. The Al 2 O 3 oxide was then deposited on the AlGaN barrier by using the USPD method [16][17][18]. Finally, the gate electrode of Ni (100 nm)/Au (50 nm) was deposited after the photolithography definition.…”

Al0.75Ga0.25N/AlxGa1-xN/Al0.75Ga0.25N/AlN/SiC Metal–Oxide–Semiconductor Heterostructure Field-Effect Transistors With Symmetrically-Graded Widegap Channel

“…Gan-based heterostructure field-effect transistors (HFETs) have been widely used due to their advantages of high speed, high power efficiency, and low switching loss [1]- [2]. Various device design approaches have been studied to increase drain current density, reduce gate leakage, and extend breakdown voltage, including uses of metal-oxide-gate (MOS-gate) [3]- [5], fieldplate (FP) [6]- [8], Schottky-source/drain [9], and trench [10] structures. Different epitaxial structures have also been investigated, such as strain-induced polarization AlGaN/GaN heterostructure [11], and lattice-matched, high polarization, and large conduction-band discontinuity ( E C ) InAlN/GaN heterostructure [12]- [13], AlN substrate [14]- [15].…”