Transient hole formation during the growth of thin metal oxide layers

Using a quinternary variable charge molecular dynamics simulation technique, we have discovered a transient hole formation phenomenon during oxidation of thin aluminum layers on Ni65Co20Fe15 substrates. Holes were found to first develop and expand at the earliest stage of the oxidation. These holes then shrank and finally disappeared as oxidation further proceeded. Thermodynamic analysis of the hole healing indicated that it is accompanied by a significant decrease in system potential energy. This suggests that the effect is largely driven by thermodynamics and is less related to the flux shadowing or kinetically introduced island coalescence. The simulations provide insights for the growth of dielectric tunnel barrier layers with reduced layer thicknesses.