Kuan Yew Cheong

Effects of Postdeposition Annealing in Argon Ambient on Metallorganic Decomposed CeO2 Gate Spin Coated on Silicon

Cerium oxide (CeO 2 ) solution was prepared by cerium(III) acetylacetonate hydrate, methanol, and acetic acid as the starting materials via the metallorganic decomposition (MOD) method. Postdeposition annealing was performed onto the MOD-derived CeO 2 films deposited onto n-type Si substrates at different temperatures (600, 800, and 1000°C) under the flow of argon gas. A slow cooling rate was then accomplished for samples to cool down to room temperature. Four orientations [(111), (200), (220), and (311)] of CeO 2 films were revealed by X-ray diffraction analysis as well as α-Ce 2 O 3 and cerium silicate (Ce 2 Si 2 O 7 ). Epitaxial-like behavior was shown in the sample annealed at 600°C due to the (200)-oriented CeO 2 film, and the dominance of this plane ceased with the increase in annealing temperature. A negative voltage shift was observed in all of the samples, indicating that positive oxide charges were trapped in the oxide as a result of the presence of oxygen vacancies. An interface trap density was extracted from the capacitance-voltage measurement, and it was related to the current density-voltage characteristics of the investigated samples. The lowest density was perceived by the sample annealed at 1000°C due to the increment in the Ce 2 Si 2 O 7 layer, reduction in total interface trap density, and effective oxide charge.

MOS Characteristics of Metallorganic-Decomposed CeO2 Spin-Coated on GaN

Metallorganic-decomposed CeO 2 has been successfully spin-coated on an n-type GaN substrate. The effect of postdeposition annealing temperature (400-1000°C) on the electrical characteristics of a CeO 2 /GaN-based metal oxide semiconductor (MOS) structure has been investigated. It has been identified that the sample annealed at the highest temperature demonstrated the highest dielectric breakdown field. The parameters that contributed to this observation have been discussed in detail in this article.

Electrical Properties of Pulsed Laser Deposited Y2O3 Gate Oxide on 4H-SiC

Yttrium oxide (Y 2 0 3 ) has been successfully deposited on n-type 4H-SiC substrates using pulsed laser deposition. The effects of postdeposition annealing temperature (400, 500, and 600°C) on the electrical properties of the Y 2 O 3 gate oxide have been studied in comparison with the as-deposited sample. The sample annealed at 600°C possessed the highest dielectric breakdown field of ∼6.5 MV cm -1 at 10- 6 A cm -2 , resulting from the lowest interface trap density and total interface trap density. The Fowler-Nordheim tunneling mechanism has been investigated on all samples and the highest value of barrier height extracted between the semiconductor and oxide conduction band edges was 2.67 eV.

Effects of post-deposition annealing ambient on band alignment of RF magnetron-sputtered Y2O3 film on gallium nitride

The effects of different post-deposition annealing ambients (oxygen, argon, forming gas (95% N2 + 5% H2), and nitrogen) on radio frequency magnetron-sputtered yttrium oxide (Y2O3) films on n-type gallium nitride (GaN) substrate were studied in this work. X-ray photoelectron spectroscopy was utilized to extract the bandgap of Y2O3 and interfacial layer as well as establishing the energy band alignment of Y2O3/interfacial layer/GaN structure. Three different structures of energy band alignment were obtained, and the change of band alignment influenced leakage current density-electrical breakdown field characteristics of the samples subjected to different post-deposition annealing ambients. Of these investigated samples, ability of the sample annealed in O2 ambient to withstand the highest electric breakdown field (approximately 6.6 MV/cm) at 10−6 A/cm2 was related to the largest conduction band offset of interfacial layer/GaN (3.77 eV) and barrier height (3.72 eV).