Patent ID: 6881263

Claim:
A method of growing a thin film onto a substrate placed in a reaction chamber according to the ALD method, said method comprising the steps of: vaporizing a reactant from a reactant source maintained at a vaporizing temperature; conducting the vaporized reactant to the reaction chamber via a first conduit; regulating the flow of said reactant so as to feed the reactant into said reaction chamber in the form of vapor-phase pulses repeatedly and alternately with vapor-phase pulses of at least one other reactant; causing said vapor-phase reactant to react with the surface of the substrate at a reaction temperature to form a thin film compound on said substrate; feeding inactive gas into said first conduit via a second conduit, connected to the first conduit at a connection point, during the time interval between the vapor-phase pulses of the reactant so as to form a gas phase barrier against the flow of the vaporized reactant from the reactant source via the first conduit into the reaction chamber; and withdrawing the inactive gas from said first conduit via a third conduit connected to the first conduit, said third conduit being maintained at a temperature equal to or higher than the condensation of the vapor-phase reactant and being connected to the first conduit at a point upstream of the second conduit; and wherein regulating the flow of said reactant comprising choking of the reactant flow while still allowing a minimum flow of said reactant between the vapor-phase pulses.