We propose a new process for forming ultra-thin metal oxide films called vapor-liquid hybrid deposition (VALID). This process consists of two steps: i) adsorption of a metal-organic or metal-halide precursor from the gas phase, and ii) liquid-phase hydrolysis of the adsorbed precursors. Al2O3 films were grown using Al(CH3)3 and water. Growth rate was 0.18 nm per cycle at room temperature. The interface layer thickness was less than 1 nm after post-deposition annealing in vacuum at 750°C. C-V and I-V characteristics of Au/Al2O3/Si capacitors fabricated using VALID were well-behaved suggesting that this concept is a viable approach to form device-quality dielectrics.