Influence of oxygen-plasma treatment on AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors with HfO₂by atomic layer deposition: leakage current and density of states reduction

Abstract

The electrical properties of AlGaN/GaN MOSHFETs with HfO 2 prepared by atomic layer deposition with and w/o oxygen-plasma treatment (further referred to as PHf-MOS and Hf-MOS) were investigated. The sub-threshold slope of the MOSHFETs (350 and 150 mV dec −1 for Hf-MOS and PHf-MOS, respectively) were lower than that for HFET (450 mV dec −1 ), which also correspond with lower leakage current of the MOSHFETs (∼10 −8 A mm −1 at −9 V for PHf-MOS). In addition, the density of the interface states at the oxide/GaN-cap layer near the conduction band edge and mid-gap (∼5×10 12 and 2×10 11 cm −2 eV −1 , respectively) after PHf-MOS was lower than that for Hf-MOS (∼3× 10 13 and 2×10 12 cm −2 eV −1 , respectively). From the x-ray photoemission spectroscopy analysis we observed a shift in the Auger Ga LMM peaks (0.6 eV) and an increase of the intensity area of the Ga-O bond in the Ga2p3 spectrum after the oxygen-plasma treatment, mainly because the GaN-cap layer was oxidized and Ga 2 O 3 was formed.

Investigation of angstrom-thick aluminium oxide passivation layers to improve the gate lag performance of GaN HEMTs

“…Based on the calculation of free energy by classical nucleation theory, most of the oxygen-derived hydroxyl groups such as OH radicals and H 2 O or O 2 will be chemisorbed near imperfections such as dangling bonds and vacancies. Looking back into Figure 7(a), the N1s spectra is deconvoluted into five main peaks [24]; three of which are assigned into Auger Ga LMM peaks, the dominant one comes from the Ga-N bond, and the one in the higher energy tail is attributed to N-O bonds. As we can see, the passivated sample has a stronger N-O related peak.…”

Normally-off AlGaN/GaN MIS-HEMT with low gate leakage current using a hydrofluoric acid pre-treatment

“…The same behavior can be probed by exploring the N1s spectra. The N1s spectra is deconvoluted into five main peaks [23]; three of which are assigned into Auger Ga LMM peaks, the dominant one comes from Ga-N bond, and the one in the higher energy tail is attributed to N-O bonds. As we can see, the same trend has been followed for N-O related peak.…”

X-ray photoelectron spectroscopy study on effects of ultra-high-pressure annealing on surface of Mg-ion-implanted GaN

“…Here, the photoelectron take-off angle θ was set at 45 o . A Ga LMM Auger spectrum was decomposed into three components according to the literature 29,30) , whereas a Ga 3d spectrum was fitted by the combined Voigt function considering the spin-orbit doublet. The intensity was normalized to the area of the Ga 3d spectrum.…”