Paper EM1-WeM12
Effect of Deposition Temperature on the Electrical Properties of ALD-HfO2 Film on GaAs
Wednesday, October 30, 2013, 11:40 am, Room 101 B
| Session: |
Electrical Testing and Defects in III-V’s |
| Presenter: |
S. Choi, Sungkyunkwan University, Republic of Korea |
| Authors: |
S. Choi, Sungkyunkwan University, Republic of Korea
Y.-C. Byun, Sungkyunkwan University, Republic of Korea
Y. An, Sungkyunkwan University, Republic of Korea
H. Kim, Sungkyunkwan University, Republic of Korea
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| Correspondent: |
Click to Email |
For the scaling of n-channel metal-oxide-semiconductor field-effect transistor (NMOSFET) down to a sub-10 nm-node, atomic layer deposition (ALD) of high-k gate dielectrics on III-V channel materials has been widely studied to achieve excellent dielectric quality comparable to that on Si. Nevertheless, there are still many remaining issues to be solved and the most important one is a poor interface quality. The high interface state density is believed to be closely associated with the existence of substrate element-related oxide bonds near the interface region [1]. In this presentation, we systematically investigated the electrical properties of ALD-HfO2 films on both n-type and p-type GaAs substrates as a function of the ALD temperature and compared with those on Si substrates. Based on several physical and chemical probing methods, we tried to understand the identity of near-interface characteristics and to correlate with the resulting electrical properties. For the initial surface preparation before the ALD process, n- and p-type GaAs substrates were cleaned with HF and S-passivated using (NH4)2S solution. For the HfO2 deposition, tetrakis (ethylmethylamino) hafnium/H2O precursors were used, and the ALD temperature was varied from 200 °C to 300 °C. According to the high frequency capacitance-voltage measurement, the frequency dispersion in the accumulation region was somewhat decreased when the deposition temperature was lowered. The interface trap density (Dit) distribution across the GaAs bandgap was estimated based on the conductance measurements conducted on both n- and p-type GaAs samples. This also exhibited a decreasing trend with decreasing ALD temperature. Detailed discussion on various physical/chemical analysis results such as X-ray photoelectron spectroscopy and time of flight-secondary ion mass spectrometry will be presented and compared with the similar experimental results performed on the Si substrates.
[1] M. M. Frank, G. D. Wilk, D. Starodub, T. Gustafsson, E. Garfunkel, Y. J. Chabal, J. Grazul, and D. A. Muller, Appl. Phys. Lett., 86, 152904 (2005).