Atomic layer deposition of lanthanum aluminum oxide nano-laminates for electrical applications

Lanthanum aluminum oxide thin films were grown by atomic layer deposition from a lanthanum precursor, tris(N,N'-diisopropylacetamidinato)lanthanum (La((i)PrAMD)(3)), trimethylaluminum and water. Smooth, amorphous films having compositions La(0.5)Al(1.5)O(3) and La(0.9)Al(1.1)O(3) were deposited on HF-last silicon and characterized without postdeposition annealing. The films contained less than 1 at. % of carbon according to Rutherford backstattering spectrometry and secondary ion mass spectrometry. A thin (9.8 nm) film showed low leakage current (<5*10(-8) A/cm(2) at 1 V for an equivalent oxide thickness of 2.9 nm), flatband voltage of -0.1 V and low hysteresis (20 mV). Thicker films had even lower leakage currents (<10(-8) A/cm(2) at 2 MV/cm) but larger flatband shifts and more hysteresis. The permittivity of the films was 13 and the dielectric strength 4 MV/cm. Cross sectional high-resolution transmission electron microscopy showed a sharp interface between the film and the silicon substrate. (C) 2004 American Institute of Physics.