ATOMIC LAYER CONTROLLED DEPOSITION OF AL2O3 FILMS USING BINARY REACTION SEQUENCE CHEMISTRY

Al2O3 films with precise thicknesses and high conformality were deposi ted using sequential surface chemical reactions. To achieve this contr olled deposition, a binary reaction for Al2O3 chemical vapor depositio n (2Al(CH3)(3) + 3H(2)O --> Al2O3 + 6CH(4)) was separated into two hal f-reactions: (A) AlOH + Al(CH3)(3) --> Al-O-Al(CH3)(2)* + CH4, (B) Al CH3 + H2O --> AlOH* + CH4, where the asterisks designate the surface species. Trimethylaluminum (Al(CH3)(3)) (TMA and H2O reactants were em ployed alternately in an ABAB... binary reaction sequence to deposit A l2O3 films on single-crystal Si(100) and porous alumina membranes with pore diameters of similar to 220 Angstrom. Ellipsometric measurements obtained a growth rate of 1.1 Angstrom/AB cycle on the Si(100) substr ate at the optimal reaction conditions, The Al2O3 films had an index o f refraction of n = 1.65 that is consistent with a film density of rho = 3.50 g/cm(3). Atomic force microscope images revealed that thr Al2O 3 films were exceptionally flat with a surface roughness of only +/-3 Angstrom (rms) after the deposition of similar to 270 Angstrom using 2 50 AB reaction cycles. Al2O3 films were also deposited inside the pens of Anodise alumina membranes. Gas flux measurements for H-2 and N-2 w ere consistent with a progressive pore reduction versus number of AB r eaction cycles. Porosimetry measurements also showed that the original pore diameter of similar to 220 Angstrom was reduced to similar to 13 0 Angstrom after 120 AB reaction cycles.