Korea Advanced Institute of Science and Technology

Suk Joong Kang

Sung Yoon Chung

Ho Yong Lee

Si Kyung Choi

Byung Sung Kang

Young Woo Rhee

Suk Pil Kim

A method of manufacturing an alumina-based ceramic includes sintering a powder compact of an iron-containing alumina powder in an atmosphere (N , 95 N -5 H , H ) of a relatively low oxygen partial pressure, and annealing in an atmosphere (80 N -20 O , O ) higher in oxygen partial pressure than the sintering atmosphere to provide an alumina-based ceramic with a grain-boundary migration layer on a surface thereof. The resulting undulated grain boundaries on the surface layer suppress and deflect the crack propagation, thereby improving the short-crack toughness. The formation of a grain-boundary migration layer on the surface of an alumina-based ceramic brings about a great improvement in short-crack related properties, including durability and wear resistance.

Method for manufacturing surface-modified alumina-based ceramics

Disclosed is a method for preparing heteroepitaxial thin films which are free of island structures which have a bad influence on the photoelectric properties and interfacial reactivity of the thin films. These heteroepitaxial thin films are deposited on grooved or curved surfaces of substrates. The use of grooved substrates relieves the coherent elastic strain from the thin films, thereby inhibiting the surface roughening and the island structure formation in the heteroepitaxial thin films. The method can be applied to all of the thin films that show island structures, including GaAs/Si and SiGe/Si typically used in semiconductor devices and various electronic parts, enabling the thin films to be flatly deposited at a significant thickness on various substrates without additionally processing.

Method for preparing heteroepitaxial thin film

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Taejeon, South Korea

Suk Joong Kang