Influence of annealing environment on the ALD-Al₂O₃/4H-SiC interface studied through XPS

Abstract

The instability of Al2O3/4H-SiC interface at various process temperatures and ambient is investigated by the annealing of Al2O3/4H-SiC in low vacuum conditions as well as in N2 environments. Atomic layer deposited Al2O3 on a 4H-SiC substrate with 3, 6 and 10 nm of thicknesses is treated at 300, 500, 700 and 900 °C under the vacuum level of 10−1 torr. The as-deposited and annealed structures are analyzed using x-ray photoelectron spectroscopy. It is hypothesized that the minute quantity of oxygen present in low vacuum conditions diffuses through thin layers of Al2O3 and helps in forming SiO2 at the interface even at low temperatures (i.e. 300 °C), which plays a pivotal role in determining the electrical properties of the interface. It is also proved that the absence of oxygen in the ambient prevents the formation of SiO2 at low temperatures. Additionally, it is observed that Al–OH is present in as-deposited layers, which gradually reduces after annealing. However, at around 700 °C, the concentration of oxygen in the whole structure increases to maximum and reduces at 900 °C.

High-Temperature Selective Emitter Design and Materials: Titanium Aluminum Nitride Alloys for Thermophotovoltaics

“…The highest binding energy (BE) peaks are assigned as Ti–O–N and Ti–O bonding rather than the shakeup satellites because O concentrations in the as-deposited (10%) and annealed (40%) samples are not negligible. Furthermore, the center of the fitted curves (yellow dashed lines in Figure c, 456.7 eV) are closer to the expected BE of Ti–O–N (456.8 eV) rather than the BE of Ti–N shake-ups (457.4 eV). , The Al 2p spectrum can also be deconvoluted to three peaks: Al–N at 74.1 eV, Al–O in Al 2 O 3 at 75.1 eV, and Al–OH in AlO x H y at 76.2 eV . The Al–OH peak is assigned to different compositions of aluminum hydroxides such as AlO­(OH), AlO­(OH) 2 , and Al­(OH) 3 .…”

“…Furthermore, the center of the fitted curves (yellow dashed lines in Figure c, 456.7 eV) are closer to the expected BE of Ti–O–N (456.8 eV) rather than the BE of Ti–N shake-ups (457.4 eV). , The Al 2p spectrum can also be deconvoluted to three peaks: Al–N at 74.1 eV, Al–O in Al 2 O 3 at 75.1 eV, and Al–OH in AlO x H y at 76.2 eV . The Al–OH peak is assigned to different compositions of aluminum hydroxides such as AlO­(OH), AlO­(OH) 2 , and Al­(OH) 3 . It is noteworthy that the intensity of the Ti–N peak relative to Ti–O and Ti–O–N peaks increases after temperature cycling, whereas the intensity of the Al–N peak relative to Al–O peak (or the Al–OH peak) decreases after the same heating cycles.…”

AlCl3@ZnO nanostructured material: an efficient green catalyst for the one-pot solvent-free synthesis of 1,4-dihydropyridines

“…The binding energy peaks at 74.4 eV and 74.7 eV signify the Al 2p 3/2 and Al 2p 1/2 energy states, respectively. This binding energy values can be assigned to Al 3+ species in Al 2 O 3 47 and AlCl 3 , 48 respectively. The binding energy at 199.58 eV denotes the Cl 2p 3/2 energy state of metal chloride.…”

X-ray Absorption Fine Structural Study of Atomic Structures and Chemical States of Dopants in 4H-SiC(0001)

“…Silicon carbide (SiC), a wide bandgap semiconductor with an indirect band structure, is attractive as a semiconductor for its excellent physical and electronic properties. − SiC exhibits a large band gap (2.3 to 3.2 eV), high temperature coefficient, high critical field strength (4–6 MV cm –1 ), and high chemical stability. − SiC-based devices show high breakdown voltage, high switching speed, and high-temperature operation. ,, …”