Atomic layer controlled deposition of Al2O3 films using binary reaction sequence chemistry

Al2O3 films with precise thicknesses and high conformality were deposited using sequential surface chemical reactions. To achieve this controlled deposition, a binary reaction for Al2O3 chemical vapor deposition (2Al(CH3)(3) + 3H(2)O --> Al2O3 + 6CH(4)) was separated into two half-reactions: (A) AlOH* + Al(CH3)(3) --> Al-O-Al(CH3)(2)* + CH4, (B) AlCH3* + H2O --> AlOH* + CH4, where the asterisks designate the surface species. Trimethylaluminum (Al(CH3)(3)) (TMA and H2O reactants were employed alternately in an ABAB... binary reaction sequence to deposit Al2O3 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) substrate at the optimal reaction conditions, The Al2O3 films had an index of 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 Al2O3 films were exceptionally flat with a surface roughness of only +/-3 Angstrom (rms) after the deposition of similar to 270 Angstrom using 250 AB reaction cycles. Al2O3 films were also deposited inside the pens of Anodise alumina membranes. Gas flux measurements for H-2 and N-2 were consistent with a progressive pore reduction versus number of AB reaction cycles. Porosimetry measurements also showed that the original pore diameter of similar to 220 Angstrom was reduced to similar to 130 Angstrom after 120 AB reaction cycles.