Thin films of ZrO2 for high-k applications employing engineered alkoxide- and amide-based MOCVD precursors

Ultrathin ZrO2 films were deposited on SiOx/Si in a multiwafer planetary metal-organic (MO)CVD reactor combined with a liquid delivery system. Two different alkoxide-based precursors, [Zr((OPr)-Pr-i)(2)(tbaoac)(2)] and [Zr((OBu)-Bu-i)(2)(tbaoac(2)] are compared with two amide-based precursors, [Zr(NEt2)(2)(dbml)(2)] and [Zr(NEtMe)(2)(guanid)(2)]. Growth rate, surface roughness, density, and crystallization behavior are compared over a wide range of deposition temperatures (400-700 degrees C). In addition, the influence of the solvents, n-butylacetate, toluene, and hexane, is discussed. The best growth results in terms of low temperature deposition rate, surface roughness, film density, and carbon content were obtained for the new [Zr(NEtMe)(2)(guanid)(2)] precursor. The electrical properties were investigated with metal-insulator-semiconductor (MIS) capacitors. The relative dielectric permittivity was in the range 17-24, depending on the precursor. Compared to standard SiO2 capacitors of similar equivalent oxide thickness, low leakage currents were obtained.