2004, Vol.14, No.3

Journal of the Korean Crystal Growth and Crystal Technology 2023 KCI Impact Factor : 0.19

pISSN : 1225-1429 / eISSN : 2234-5078
https://journal.kci.go.kr/jkcgct

In this work, HA/TiO2 biocomposite to get high mechanical properties with biocompatibility were prepared. HA/ TiO2 biocomposite powders were prepared by mixing TiO2 and HA powders which were synthesized through sol-gel, precipitation and hydrothermal methods. The mixing ratio was fixed at 1 : 1 ratio (HA/TiO2, wt%). HA/TiO2 biocomposite powders showed different microstructures depending on their particle size and shape. The smaller particles were coated on the surface of larger particles, whereas they were well mixed and dispersed when both TiO2 and HA were nanocrystallites. HA/ TiO2 biocomposite powders with homogeneous microstructure showed high sintered density and good mechanical properties.

The variation of electrical properties of (Ba,Sr)TiO3 [BST] thin films for Metal-Insulator-Semiconductor (MIS)capacitors was investigated. BST thin films were deposited on p-Si(10) substrates by the RF magnetron sputtering withtemperature range of 500~600oC. The dielectric properties of MIS capacitors consisting of Al/BST/SiO2/Si sandwichstructure were measured for various conditions. We examined the characteristics of MIS capacitor with various oxygenpressure, substrate temperature and (Ba+Sr)/Ti ratio. It was found that the leakage curent was reduced in MIS capacitorwith high quality SiO2 layer was grown on bare p-Si substrate by thermal oxidation. The BST MIS structure showedrelatively high capacitance even though it is the combination of high-dielectric BST thin films and SiO2 layer. The chargestate densities of the MIS capacitors and Current-voltage characteristics of the MIS capacitor were investigated. By applyingSiO2 layer between BST thin films and Si substrate, low leakage current of 10-10 order was observed.

This paper reports a potential problem in the electrical performance of the silicide film to silicon contacts withrespect to the scaling trend in integrated circuit (IC) devices. The effects of elastic strain on the aglomeration of thecoherent silicide film embedded in an infinite matrix are studied employing continuum linear elasticity and finite-differencenumerical method. The interface atomic difusion is taken to be the dominant transport mechanism where both capilarityand elastic strain are considered for the driving forces. Under plane strain condition with elasticaly homogeneous andanisotropic system with cubic symetry, the dilatational misfit and the tetragonal misfit in the direction parallel to the filmthickness are considered. The numerical results on the shape evolution agree with the known trend that the equilibriumaspect ratio of the film increases with the elastic strain intensity. When the elastic strain intensity is taken to be only afunction of the film size, the flat film morphology with a large aspect ratio becomes increasingly unstable since theequilibrium aspect ratio decreases, as the film scales. The shape evolution results in a large decrease in contact to siliconarea, and may deteriorate the electrical performances.