Thin film deposition method including using atomic layer deposition without purging between introducing the gaseous reactants

A method of fabricating a thin film using atomic layer deposition in a first chamber where a heater and a suscepter are located, the method comprising the steps of:

• disposing an object on the susceptor so as to form the thin film thereon;
• heating the object;
• a first sub-step of introducing a first gaseous reactant into the first chamber such that the first gaseous reactant is absorbed on the object to form an absorption layer;
• a second sub-step of introducing a second gaseous reactant into the first chamber sequentially after the first sub-step such that the second gaseous reactant reacts with the absorption layer absorbed on the object;
• and
• a third sub-step of introducing a reducing gas into the first chamber such that the reducing gas reduces by-products and impurities of the first and second gaseous reactants, said method further comprising:
• the step of thermal-treating the object in a second chamber after the third sub-step when the deposited thin film is used as a dielectric layer for the electric device, wherein no purging sub-step occurs between the first, second, and third sub-steps.