Thermal vaporization and deposition of gallium oxide in hydrogen (original) (raw)
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Chemistry of Materials, 2004
The reaction of gallium trichloride and methanol under atmospheric pressure chemical vapor deposition conditions leads to the production of gallium oxide thin films on a variety of substrates. Scanning electron microscopy (SEM) indicated that an island growth mechanism predominated. X-ray photoelectron spectroscopy (XPS) revealed binding energy shifts of 530.6 eV for O 1s and 20.3 eV for Ga 3d. The films were X-ray amorphous. Energydispersive X-ray analysis (EDXA) and electron probe microanalysis (EPMA) gave coherent elemental compositions, indicating that a single phase Ga 2 O 3 was made, with negligible impurity levels. The films showed little optical reflectance (∼10%) and 65-75% total transmission from 400 to 800 nm. Gas-sensing experiments indicated that the films responded best to a reducing gas at 450°C.
Chemical Vapor Deposition of Ga2O3 Thin Films on Si Substrates
Bulletin of The Korean Chemical Society, 2002
Amorphous Ga 2 O 3 films have been grown on Si(100) substrates by metal organic chemical vapor deposition (MOCVD) using gallium isopropoxide, Ga(O i Pr) 3 , as single precursor. Deposition was carried out in the substrate temperature range 400-800 °C. X-ray photoelectron spectroscopy (XPS) analysis revealed deposition of stoichiometric Ga 2 O 3 thin films at 500-600 °C. XPS depth profiling by Ar + ion sputtering indicated that carbon contamination exists mostly in the surface region with less than 3.5% content in the film. Microscopic images of the films by scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed formation of grains of approximately 20-40 nm in size on the film surfaces. The root-mean-square surface roughness from an AFM image was ∼10 A. The interfacial layer of the Ga 2 O 3 /Si was measured to be ∼35 A thick by cross-sectional transmission electron microscopy (TEM). From the analysis of gaseous products of the CVD reaction by gas chromatography-m...
Effect of annealing in argon on the properties of thermally deposited gallium-oxide films
Semiconductors, 2013
The effect of the annealing temperature on the I-V, C-I, and G-V characteristics and transpar ency of gallium oxide films is investigated. The films are fabricated by the thermal evaporation of Ga 2 O 3 powder on n GaAs wafers. It is shown that the films which are amorphous after deposition crystallize upon annealing at temperatures T an ≥ 800°C. The electrical characteristics and photoresponse of the V/Ni-GaAs-GaAs-Ga x O y-V/Ni samples to visible radiation depend on the structure and phase composition of the films.
Low temperature Ga2O3 atomic layer deposition using gallium tri-isopropoxide and water
Thin Solid Films, 2013
Ga 2 O 3 atomic layer deposition (ALD) was carried out using gallium tri-isopropoxide (GTIP) as a gallium source and H 2 O as an oxygen source at a low temperature (150°C). The Ga 2 O 3 ALD films show amorphous, smooth, and transparent behavior. The growth behavior and a variety of optical, structural, and electrical properties were investigated by various measurements. The growth behavior of Ga 2 O 3 ALD using GTIP reveals a typical ALD process, and Ga 2 O 3 films on glass substrates show outstanding transmittance (over 90%). The Ga:O ratio was measured as 1:1.7 by the Rutherford backscattering spectrometry, and auger electron spectroscopy confirmed that there was no carbon impurity (under the detection limit). The surface morphology was investigated through an atomic force microscope analysis, and all of the films deposited at 150, 200, and 250°C showed smooth and featureless characteristics. Ga 2 O 3 ALD thin film shows excellent leakage current (1 × 10 −11 A at 1 MV/cm) and a very suitable breakdown field (6.5-7.6 MV/cm) as compared to previously reported Ga 2 O 3 films. Also, the dielectric constant of the films is similar to that of conventional Ga 2 O 3 films (about 9.23).
Thin Solid Films, 2020
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Materials Today: Proceedings, 2019
The evolution of different oxidation states during thermal oxidation of (100) oriented Ge substrate was investigated with X-ray photoelectron spectroscopic analysis. The thermally grown oxides in the temperature range of 380 to 500 o C were found to consist of four different oxidation states of Ge, namely, Ge 1+ , Ge 2+ , Ge 3+ , and Ge 4+. The fractional composition of the oxide species is seen to be dependent on oxidation temperature. Spectroscopic depth profiling reveals variation of oxide composition along the depth of the oxide layer with a large concentration of GeO 2 near the oxide surface and a large concentration of suboxides near the oxide/Ge interface. The results obtained in the investigation will help in achieving greater insight into the thermal oxidation process of Ge.
1990
Thick (>200 _), uniform, oxide layers have been produced on GaAs (110) and (100) by reacting the substrate (Ts<160°C) with high translational energy (1-3 eV) neutral atomic oxygen at flux levels of=100 monolayers/second. The Ga and As species are formed in their h[ghest oxidation states respectively which implies formation of either Ga20 3 and As20 5 or GaAsO 4. Raman spectroscopy indicates that there is no metallic (amorphous or crystalline) As in the oxide or at the interface between the oxide and substrate and that there is no appreciable oxidation induced disorder of the substrate as is seen in high temperature thermal oxidation processes.
Effect of O2 plasma exposure time during atomic layer deposition of amorphous gallium oxide
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films
Amorphous gallium oxide thin films were grown by plasma-enhanced atomic layer deposition on (100) silicon substrates from trimethylgallium Ga(CH3)3 precursor and oxygen plasma. At 200 °C, the growth per cycle is in the range of 0.65–0.70 Å for O2 plasma exposure times ranging from 3 up to 30 s during each cycle. The effect of O2 plasma exposure times on the interfacial SiOx regrowth and the electrical properties was investigated. In situ spectroscopic ellipsometry shows that the SiOx regrowth occurs during the first three cycles and is limited to 0.27 nm for plasma times as long as 30 s. Increasing the O2 plasma exposure during each ALD cycle leads to a drastic decrease in the leakage current density (more than 5 orders of magnitude for 30 nm films), which is linked to the suppression of oxygen vacancy states as evidenced by spectroscopic ellipsometry. Interestingly, an increase in the dielectric constant with increasing O2 plasma exposure time is observed, reaching a value of εr∼14...
Effect of Substrate Orientation on the Growth of Germanium Oxide in Dry Oxygen Ambience
IOP Conference Series: Materials Science and Engineering, 2017
The present investigation deals with the effect of substrate orientation effect on the growth of thermally oxidized Ge. The thermal oxidation was performed at temperature between 375 and 550°C in dry oxygen ambient under atmospheric pressure. The thickness of thermally oxidized Ge films was measured by spectroscopic ellipsometry and the chemical bonding structures were characterized by using x-ray photoelectron spectroscopy (XPS). No orientation dependence was observed for the oxidation at temperature of 375°C while for oxidation at 490 and 550°C, Ge oxidation and GeO desorption rate of (100) orientation yield higher rate than (111). The larger atomic space of (100) orientation explains the higher oxidation and desorption rate at Ge surface.
Formation and stability of germanium oxide induced by atomic oxygen exposure
Materials Science in Semiconductor Processing, 2006
The formation of a stable germanium oxide film obtained upon exposure of Ge(0 0 1) surface to atomic oxygen is characterized as a function of the substrate temperature using X-ray photoelectron spectroscopy. Although the atomic oxygen is chemisorbed by forming a mixture of dioxide and sub-stoichiometric oxide species already at room temperature, the best condition to obtain a largely dominant dioxide component is obtained at 300 1C. The evolution of the oxide with temperature is investigated by means of annealing experiments. r