Search

We present a theoretical study on the point defects in ZrO2–silicon interfaces using molecular dynamics (MD) calculations. A super-cell model that contains 9 atomic layers of silicon and 9 atomic layers of ZrO2 was used for the simulation. Three atomic layers containing 17 oxygen atoms, eight silicon atoms, and nine Zr atoms were used to simulate the ZrO2–silicon interface. We then performed density functional theory (DFT) with plane-wave basis to calculate the interface band structure. Results demonstrate that the stretched Zr–O bonds at the interface would produce some defect levels in the band gap. Particularly, the defect levels originated from the interstitial oxygen atoms are located close to the bottom of the ZrO2 conduction band and hence it will affect the electrical properties of the gate dielectrics. [ABSTRACT FROM AUTHOR]

An investigation has been made of the elementary surface reactions of alane and its surface dissociation products using density functional theory and a cluster model to elucidate the reaction mechanism of the deposition of aluminium in aluminium chemical vapour deposition (Al-CVD) using dimethylethylamine alane (DMEAA). Molecular structures, potential energies, and normal mode frequencies of the reactants, the products, and the transition states were calculated for each of the surface elementary reactions. Based on transition state theory, rate constants were estimated from the calculation results. The proposed reaction mechanism is the following. DMEAA is adsorbed onto an aluminium surface without any dissociation in the gas phase; DMEAA dissociates into dimethylethylamine (DMEA) and alane on the surface; DMEA is desorbed and alane remains adsorbed; the adsorbed alane molecules dissociate to AlH[sub 2], AlH, and H on the surface; hydrogen molecules to be desorbed are produced from the hydrogen atoms of AlH whose aluminium atoms form a quasi-aluminium surface on the original surface. The cluster size and structure dependence in quantum chemical calculations has also been considered using model clusters. [ABSTRACT FROM AUTHOR]