Jae-Gon Kim

Effect of partial pressure of the reactant gas on the chemical vapour deposition of Al2O3

Abstract Films of Al 2 O 3 were deposited onto TiN-coated cemented carbide substrates by a chemical vapour deposition technique using AlCl 3 , CO 2 and H 2 gases. The effects of the deposition temperature and the partial pressures of the reactants on the final structure of the Al 2 O 3 film were investigated, especially the effect of the supersaturations of the reactants (H 2 O and AlCl 3 ) on the final structure of the Al 2 O 3 film. The supersaturations of the reactants are calculated assuming chemical equilibria. It is found that the deposition rate of Al 2 O 3 is limited by both the AlCl 3 concentration and the [H 2 ]/[CO 2 ] ratio, but the crystal size of Al 2 O 3 film decreases with increasing H 2 O supersaturation. The supersaturation of AlCl 3 , however, seems not to affect the crystal size of Al 2 O 3 film under our experimental conditions. It is also found that the crystallographic structure of the Al 2 O 3 film changes from random orientation to (10 1 4)-preferred orientation with increasing deposition temperature.

A space partitioning method for facility layout problems with shape constraints

This paper focuses on facility layout problems with shape constraints. A heuristic algorithm is developed for the problems with the objective of minimizing the sum of rectilinear distances weighted by flow amounts between the facilities. The suggested algorithm is a simulated annealing algorithm in which a solution is encoded as a matrix that has information about relative locations of the facilities on the floor. A block layout is constructed by partitioning the floor into a set of rectangular blocks according to the information while satisfying the areas of the facilities. In this paper, three methods are suggested for the partitioning procedure and they are employed in the simulated annealing algorithm. The results of computational experiments show that the proposed algorithm performs better than two existing algorithms.

The effects of reaction parameters on the deposition characteristics in Al2O3 CVD

Deposits of aluminum oxides (Al2O3) have been formed by a chemical vapor deposition (CVD) technique involving the application of gas mixtures of AlCl3, CO2, and H2 onto TiN coated cemented carbide substrates. The relationships between the deposition rate and various reaction parameters such as the gas flow rate, the deposition temperature, the composition of reactant gases, and the system pressure were studied. The CVD of Al2O3 is a thermally activated process and limited by the surface chemical reaction. The apparent activation energy is about 36 kcal/mol at 50 Torr and decreases with the increasing system pressure. The dependence of the deposition rate on the reactant gas composition is affected by the variation of the relative contents of the aluminum donor and the oxygen donor. At a low AlCl3 mole fraction, the deposition rate increases with the AlCl3 mole fraction; however, at higher AlCl3 mole fractions than 1.0×10−2 the deposition rate is mainly influenced by the H2O‐forming reaction between CO2 an...

The deposition rate and properties of the deposit in plasma enhanced chemical vapor deposition of TiN

Titanium nitride (TiN) films were deposited onto tool steels and cemented carbide cutting tools by plasma enhanced chemical vapor deposition (PECVD) using a gaseous mixture of TiCl4, N2, H2, and Ar in order to find out the effects of the deposition temperature and rf power density on the deposition rate and properties of deposited TiN. The deposition rate and crystallinity of the deposited TiN was affected by the deposition temperature as well as the plasma power density. The deposition rate was decreased with an increase in deposition temperature between 270 and 430u2009°C. The crystallinity of deposited TiN was improved by an increase in deposition temperature as well as rf power density. Crystalline TiN was obtained above 300u2009°C and showed a strong crystallographic preferred orientation of 〈200〉. TiN layers deposited by PECVD using TiCl4 as a reactant contained chlorine, the content of which was increased with a decrease in deposition temperature. Oxygen at the interface between the TiN deposited layer and...

The effect of reactant gas composition on the plasmaenhanced chemical vapour deposition of TiN

Wear-resistant titanium nitride (TiN) coatings could be obtained at a deposition temperature of 400 °C by r.f. glow discharge plasma-enhanced chemical vapour deposition (PECVD). TiN deposition was performed on tool steels and cemeted carbide cutting tools by the PECVD technique using a gaseous mixture of TiCl4, N2, H2 and argon in order to determine the effect of the reactant gas composition on the PECVD of TiN. The experimental results show a considerable difference in the deposition rates and the constituents of the deposits according to the inlet fractions of reactant gases as well as the substrate materials. However, the atomic ratio of the TiN deposited by PECVD is not affected by reactant gas composition unless the deposited layer incorporates iron. The deposited TiN layer contains chlorine, and its content can be reduced by increasing the H2 inlet fraction. At high N2 inlet fractions, the deposited layer contains iron and the atomic ratio of nitrogen to titanium is decreased. The surface of the deposited TiN is very uniform and the films are composed of extremely fine grains of TiN.

Nucleation and growth of aluminium oxide on silicon in the CVD process

Films of aluminium oxide have been formed on single crystal silicon substrates using AlCl3-CO2-H2 gas mixtures in a cold-walled chemical vapour deposition (CVD) reactor. The nucleation and subsequent growth of the deposit have been observed under the varying process parameters. It is found that the nucleation and growth of the Al2O3 are dependent on the H2O flux and H2O supersaturation. An activation energy of 34.8 Kcal mol−1 is obtained for the growth rate indicating that the CVD of Al2O3 on silicon is a thermally activated process and limited by surface reaction. Scanning electron micrographs (SEM) show that the deposited films are amorphous at low temperature, 850° C, but change to fine grained polycrystalline structure at high temperature, 1000° C.