Room temperature photo‐CVD SiO₂ layers on AlGaN and AlGaN/GaN MOS‐HFETs

Abstract

High quality SiO2 layers were successfully deposited onto AlGaN by photo‐chemical vapor deposition (photo‐CVD) using D2 lamp as the excitation source at room temperature. The resulting interface state density was only 8.86 × 1011 cm–2 eV–1. With a 2 µm gate, it was found that maximum drain–source current, maximum transconductance (gm,max) and gate voltage swing (GVS) of the fabricated nitride‐based metal–oxide–semiconductor heterostructure field effect transistors (MOS‐HFETs) were 225 mA/mm, 33 mS/mm and 6.5 V, respectively. Compared with metal‐semiconductor HFETs (MES‐HFETs), it was found that noise power density of MOS‐HFETs was lower and presented pure 1/f noise with smaller trapping effects. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Simulations of Capacitance–Voltage–Temperature Behavior of Metal/Insulator/AlGaN and Metal/Insulator/AlGaN/GaN Structures

“…V (V) - qualitative because of the variety of device parameters (insulator permittivity and thickness, AlGaN composition, doping, and others). The 1 MHz C-V results by Wang et al 27) for Al/SiO 2 (50 nm)/Al 0:22 Ga 0:78 N capacitor at RT (Fig. 3 Temperature-dependent C-V analyses of GaN MIS capacitors were performed by Matocha et al 29) for Al/ SiO 2 (65 nm)/GaN capacitor at up to 175 C and by Bae et al 30) for Al/SiO 2 /nitrided-Ga As has been mentioned in §3.1, the stretch-out of RT C-V characteristics of the metal/insulator/AlGaN/GaN capacitors due to the AlGaN/GaN interface states should be very tiny in contemporary devices because of a low level of D it ðEÞ at this interface.…”

Investigation of O3‐Al2O3/H2O‐Al2O3 dielectric bilayer deposited by atomic‐layer deposition for GaN MOS capacitors

“…Meanwhile, for Al‐GaN/GaN normally off HFETs, the use of MOS structure may increase the positive threshold voltage that was needed for the practical demands of the devices. Many materials were proposed for the gate dielectric such as SiO 2 , MgO , Ga 2 O 3 , Al 2 O 3 , and HfO 2 . Among these materials, Al 2 O 3 grown by atomic‐layer deposition (ALD) has become one of the leading candidates because of its outstanding features, e.g., large bandgap, high dielectric constant, good interface quality with AlGaN and GaN.…”