ZIRCONIUM DIOXIDE THIN FILMS FOR high-κ APPLICATIONS BY MOCVD FROM NOVEL MONONUCLEAR PRECURSORS

摘要

ZrO_2 thin films with thickness between 2 and 30 rnn were deposited on SiO_x/Si in a multi-wafer planetary MOCVD reactor combined with a liquid delivery system. Two different precursors, Zr(Opr~I)_2(tbaoac)_2 and Zr(Obu~t)2(tbaoac)_2 and two different solvents, n-butylacetate and hexane are used for the deposition. Growth rate, surface roughness, density and crystallization behavior are compared over a wide range of deposition temperatures (400-700℃). Crystallization temperature of films from Zr(Opr~I)_2(tbaoac)_2 was dependent on the choice of the solvent: for hexane it was 50-100℃ higher than for n-butylacetate. Film density similarly depends on deposition temperature and type of solvent, and bulk density of 5.8 gcm~(-3) is reached at high deposition temperature. These differences are correlated with the different carbon incorporation. The electrical properties have been investigated with metal-insulator-semiconductor capacitors. For amorphous films the dielectric constant was around 20 and minimum equivalent oxide thickness obtained was ～2 nm. Compared to SiO_2 low leakage currents were obtained.