| AVS 61st International Symposium & Exhibition | |
| Thin Film | Monday Sessions |
| Session TF+PS-MoA |
| Session: | ALD Surface Reactions and Precursors |
| Presenter: | Liwang 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 |
In situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy was utilized to study the surface reactions and interface evolution during the Atomic Layer Deposition (ALD) of HfO2 on GaAs(100) surfaces. The chemistry studied involves the use of tetrakis (dimethylamino) hafnium (TDMAH) and H2O. The experiments were performed on chemical oxide and HF etched GaAs(100) starting surfaces. For the deposition of HfO2 on chemical oxide GaAs surface at 275°C, which corresponds to the optimal ALD process temperature, considerable arsenic oxide consumption was observed at the 1st TDMAH exposure. The arsenic oxide removal continued during subsequent ALD cycles albeit at a reduced rate. For similar experiments performed at 200°C, the arsenic oxide consumption was significantly lower than that at 275°C in agreement with the observations of Suri et al.1 A clear ligand exchange process is identified through the alternate appearance of the CH and OH terminated surfaces. However, additional byproducts that contain -C=N- bonds are produced during the water pulse and accumulate in the film. Isotope exchange experiments indicate that these species are compatible with the formation of methylmethyleneimine (MMI) that may be produced through a beta hydride elimination pathway. 2,3
[1] R. Suri, D. J. Lichtenwalner, and V. Misra, Appl. Phys. Lett. 96, 112905 (2010).
[2] C. M. Truong, P. J. Chen, J. S. Corneille, W. S. Oh, and D. W. Goodman, J. Phys. Chem. 99, 8831 (1995).
[3] M. Bouman and F. Zaera, J. Electrochem. Soc. 158, D524 (2011).