Silicon out-diffusion and aluminum in-diffusion in devices with atomic-layer deposited La2O3 thin films

The use of Al as an electrode in metal-insulator-semiconductor devices contg. La2O3 is impaired by unacceptable leakage current levels. Time of flight secondary ion mass spectroscopy depth profiling shows a significant amt. of Si out-diffusion from the substrate and Al in-diffusion towards the oxide. By using Ti nitride as the electrode, the Si out-diffusion is suppressed, which improves the device performance. Despite the larger coordination no. of the La ions in the oxide, Al acts as a sink for Si, thus driving the out-diffusion of Si. (c) 2008 American Institute of Physics. [on SciFinder (R)