| AVS 60th International Symposium and Exhibition | |
| Thin Film | Monday Sessions |
| Session TF+AS+SE+SS-MoA |
| Session: | ALD/MLD Surface Reactions, Precursors, and Properties |
| Presenter: | L. Ye, University of Maryland, Baltimore County |
| Authors: | L. Ye, University of Maryland, Baltimore County T. Gougousi, University of Maryland, Baltimore County |
| Correspondent: | Click to Email |
The atomic level mechanisms during the deposition of TiO2 on etched and chemical oxide Si (100) and GaAs (100) surfaces from tetrakis dimethyl amino titanium (TDMAT) and H2O at 100 and 200C have been studied using in situ attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The adsorption of TDMAT on Si and GaAs surfaces is confirmed by the observation of CH and NC vibration modes. Exposure to H2O removes most of the CH bonds, but species associated with reaction by-products remain on the surface and increase in intensity as the deposition progresses. For the deposition on both chemical oxide and hydrogen terminated Si surfaces at 100 and 200C, the amount of TDMAT adsorbed on the surfaces generally decreases with increasing number of cycles and reaches similar steady state coverage at about the 20th cycle of deposition. For depositions on hydrogen terminated Si surfaces, about 50% of the initial Si-H bonds remain unreacted after 20 process cycles. For deposition on both Si and GaAs surfaces, C=O bonds at 1595 cm-1 associated with formate species accumulate during the deposition. The use of GaAs internal reflection elements allows extension of the useful range just around 700 cm-1 permitting possible observation of the precursor reaction with the surface As and Ga oxides.