Role of Ga2O3 template thickness and gadolinium mole fraction in GdxGa0.4−xO0.6/Ga2O3 gate dielectric stacks on GaAs

Abstract

Amorphous GdxGa0.4−xO0.6/Ga2O3 gate dielectric stacks have been grown onto the GaAs(001) surface by molecular beam epitaxy using high temperature effusion cells. The Ga2O3 template thickness and the Gd mole percent have been systematically varied from 73 to 0 Å and from 8.8 to 22 at. % (0.088⩽x⩽0.22), respectively. Oxide/n-type GaAs samples have been characterized by high-frequency capacitance–voltage measurements. Optimum gate oxide stack and oxide/GaAs interface properties are obtained with a Ga2O3 template thickness of 9–11 Å and a minimum Gd mole percent of 15–17 at. %. While gate oxide films with thicker Ga2O3 templates and/or lower Gd mole fraction show kinks in capacitance–voltage measurements attributed to charge trapping in the oxide, thinner Ga2O3 templates lead to strong stretch-out of capacitance–voltage curves indicating severely degraded oxide/GaAs interface properties.

Ab-initio investigation of structural, electronic and optical properties of InxGa1−xAs, GaAs1−yPy ternary and InxGa1−xAs1−yPy quaternary semiconductor alloys

“…Only a few examples include high-electronmobility and heterostructure bipolar transistors, diode lasers, light-emitting diodes, photodetectors, electro-optic modulators, and frequency-mixing components [1][2][3][4]. The operating characteristics of these devices depend critically on the physical properties of the constituent materials, which are often combined in quantum heterostructures containing carriers confined to dimensions * Corresponding author.…”

Optical and electrical properties of amorphous GdxGa0.4−xO0.6 films in GdxGa0.4−xO0.6/Ga2O3 gate dielectric stacks on GaAs

“…8,9 It was suggested as early as 1995 that the low D it property of the oxide-GaAs interface is solely provided by Ga 2 O 3 and that the resistivity of the bulk oxide is related to the depth profile of the Gd concentration. 8,9 Recent studies confirmed the distinctively different roles of Gd mole fraction 10 This letter reports on a systematic study of optical and electrical properties of Gd x Ga 0.4Ϫx O 0.6 films as a function of Gd mole fraction x. These films are part of Gd x Ga 0.4Ϫx O 0.6 /Ga 2 O 3 gate dielectric stacks grown on GaAs͑001͒.…”

Controlled band offset in (Gd2O3)1−x(SiO2)x(0⩽x⩽1)∕n–GaAs (001) structure

“…5͑b͒, indicates that Fowler-Nordheim ͑FN͒ tunneling is the dominant conduction mechanism. The barrier height was indirectly compared from the negative slope of the linear fitting at higher field, 13 which is accordant with the previous results.…”

“…The degradation in the film of x = 0.82 is due to charge trapping at the defect site in the oxide. 13 The log͑J / E 2 ͒ vs 1 / E plot in the inset of Fig. 5͑b͒, indicates that Fowler-Nordheim ͑FN͒ tunneling is the dominant conduction mechanism.…”