Evaluation of barrier height and thickness in tunneling junctions by numerical calculation on tunnel probability

The barrier height and thickness of Al/AlOx/Al and Co/AlOx/Co tunneling junctions were evaluated from current–voltage (I–V) data by fitting the numerical calculation of tunnel probability. As a calculation model, one-layer and two-layer models of AlOx were assumed. The results of the one-layer model showed a physically unexpected relation between barrier height and thickness. The two-layer model showed no such relation. The results of the two-layer model showed that insulators of Al/AlOx/Al junctions were oxidized more incompletely as oxidation time was increased and insulators of Co/AlOx/Co junctions were oxidized more completely at higher oxidation temperatures.