Controlling the Temperature of a Substrate in a Film Deposition Apparatus

A method for affecting a temperature of a substrate on a pedestal in a film deposition apparatus for rapidly cycling the temperature of said substrate during an atomic layer deposition (ALD) process, the deposition apparatus having a process chamber area for processing a top surface of said substrate and having a substrate backside space between said substrate and said pedestal, the method comprising:

• a. causing a temperature of said substrate to be at a first temperature by controlling irradiation of a top surface of said substrate with an energy source and providing a heat transferring gas in said backside space between said pedestal and said substrate at a first pressure to cool said substrate, the heat transferring gas contacting a bottom surface of said substrate, wherein said pedestal is cool relative to said substrate, wherein said heat transferring gas thermally couples said substrate to said pedestal to remove heat from said substrate, wherein a gas pressure in said backside space is different from a gas pressure in said process chamber area;
• b. introducing a first reactant gas into said process chamber area, such that substantially at least one monolayer of said first reactant gas is adsorbed onto said substrate, wherein said first temperature is low enough to prevent decomposition of said first reactant gas;
• c. evacuating any excess of said first reactant gas from said process chamber area;
• d. causing a temperature of said substrate to be at a second temperature by controlling irradiation of said top surface of said substrate by said energy source and providing said heat transferring gas in said backside space between said pedestal and said substrate at a lower pressure, relative to said first pressure, wherein a gas pressure in said backside space is different from a gas pressure in said process chamber area;
• e. introducing a second reactant gas into said process chamber area to react with said first reactant gas to deposit a monolayer of a single material over said substrate during a single ALD cycle, wherein said second temperature is higher than said first temperature to cause a reaction between said first reactant and said second reactant on the substrate to deposit a film of material on said substrate;
• f. evacuating any excess of said second reactant gas from said chamber;
• and
• g. repeating steps a through f to form successive films of said material on said substrate until said successive films are of a desired thickness.