15 October 2012 Optical and electrical characterization of atomic layer deposited (ALD) HfO2/p-GaAs MOS capacitors
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Proceedings Volume 8549, 16th International Workshop on Physics of Semiconductor Devices; 85493I (2012); doi: 10.1117/12.924341
Event: 16th International Workshop on Physics of Semiconductor Devices, 2011, Kanpur, India
Abstract
The HfO2/p-GaAs metal-oxide-semiconductor (MOS) structures have been fabricated by developing and simulating an optimized process recipe. The optical dielectric constants and refractive indices of atomic-layer-deposited (ALD) HfO2 films and the GaAs substrate are extracted from spectroscopic ellipsometer (SE) measurements. The quality of interface and that of the ALD HfO2 films is investigated by analyzing capacitance-voltage (C-V) and conductance-voltage (G-V) data. Simulations of C-V and G-V data have also been performed for a similar process recipe to comprehensively understand the electrical quality of the dielectric layer. The optical dielectric constants for HfO2 and GaAs layers are obtained to be 4.5-3.6 and 10-25, respectively, while their refractive indices are obtained to be 2.12-1.89 and 3-5.2, respectively. A frequency dispersion of the C-V graphs is observed indicating the presence of a Ga2O3 interfacial layer which has been confirmed from the device simulation. A flat band voltage shift of − (0.68-1.05) eV and interface state density of (5×1011 - 1 ×1012) cm-2 eV-1 are obtained.
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Anindita Das, Sanatan Chattopadhyay, Goutam Kumar Dalapati, Dongzhi Chi, M. K. Kumar, "Optical and electrical characterization of atomic layer deposited (ALD) HfO2/p-GaAs MOS capacitors", Proc. SPIE 8549, 16th International Workshop on Physics of Semiconductor Devices, 85493I (15 October 2012); doi: 10.1117/12.924341; http://dx.doi.org/10.1117/12.924341
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KEYWORDS
Dielectrics

Atomic layer deposition

Molybdenum

Gallium arsenide

Interfaces

Capacitors

Refractive index

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