In situ time-resolved optical studies of Al oxidation for magnetic tunnel junctions

Real-time in situ optical measurements were performed during the oxidation of ultrathin Al layers with a view to study oxidation kinetics and provide process control. The optical technique combines high temporal and spatial r esolution with submonolayer sensitivity. In situ x-ray photoelectron spectr oscopy measurements on the same samples are in good agreement, confirming t he accuracy and sensitivity of the technique. For all thicknesses studied, the initial oxidation is extremely rapid, with quasilogarithmic behavior ov er the whole time scale. This technique could be utilized to study a wide v ariety of in situ reactive processes. (C) 2001 American Institute of Physic s.