Tailoring the material and electronic properties of ultra-thin ZrO2 films for microelectronics application

ZrO2 thin film was investigated in this work to replace SiO2 as the gate dielectric material in future metal-oxide-semiconductor field effect transistors (MOSFET). ZrO2 thin film was deposited on planar Si (100) wafers by an atomic layer chemical vapor deposition (AL-CVD) process using a zirconium (IV) t-butoxide Zr(OC4H9)(4) precursor and oxygen. Atomic layer controlled deposition of ZrO2 was achieved at 300degreesC to 400degreesC where the reaction was thermally activated with an activation energy of 29 kcal/mol, consistent with a beta-hydride elimination mechanism leading to ZrO2 deposition. The deposited ZrO2 thin film was stoichiometric, amorphous, uniform, smooth, and conformal. An interfacial zirconium silicate formation was observed by the high-resolution transmission electron microscopy. The characterized electrical properties of ZrO2 including its high dielectric constant, small C-V hysteresis, and low interfacial density, are ideal for the MOSFET application.