AVS 47th International Symposium
    Thin Films Monday Sessions
       Session TF-MoA

Invited Paper TF-MoA5
Radical Enhanced Atomic Layer Deposition (ALD) of Diffusion Barrier Films at Low Temperatures

Monday, October 2, 2000, 3:20 pm, Room 203

Session: Atomic Layer Chemical Vapor Deposition II
Presenter: A. Sherman, Sherman & Associates
Authors: A. Sherman, Sherman & Associates
F. Turner, Sherman & Associates
C. Pan, ASM America
S.M. Rossnagel, IBM T.J. Watson Research Center
Correspondent: Click to Email
Atomic Layer Deposition (ALD) processes can be extended to low deposition temperatures by the use of an appropriate free radical in place of a conventional molecular reactant. Typically, the ALD process has been carried out using stable gaseous reactants, and the surface reaction was thermally driven in the temperature range of 300-400°C. Radical enhanced ALD has been carried out for the deposition of Ti, TiN, Ta, TaN, and Al@sub 2@O@sub 3@ at temperatures from room temperature to 400°C. Remote inductive plasma sources, operating at frequencies from 400 KHz to 13.56 MHz were used to generate free radicals from O@sub 2@, N@sub 2@, H@sub 2@ and NH@sub 3@ gas sources. Residual gases in the reactor chamber were removed after each dosing step by evacuating the chamber with a vacuum pump, rather than purging with an inert gas. Titanium films were deposited from 25-250°C using titanium tetrachloride and hydrogen. The conformality in high aspect ratio vias and the thickness uniformity across 200 mm wafers was excellent. Tantalum films were deposited using tantalum pentachloride and hydrogen at temperatures from 25-400°C. Additional experiments have been carried out using TDMAT (tetrakis(dimethylamido)titanium) at room temperature to deposit titanium bearing films. Aluminum oxide films were deposited at room temperature from TMA (trimethyl aluminum) and oxygen. Experimental results, including SEM observations in high aspect ratio features, as well as chemical analysis (RBS, XPS, AES) and structural (XRD) measurements will be reported.