15 October 2012 Effects of constant voltage stressing on HfTaOx/SiGe gate stack
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Proceedings Volume 8549, 16th International Workshop on Physics of Semiconductor Devices; 854925 (2012); doi: 10.1117/12.926999
Event: 16th International Workshop on Physics of Semiconductor Devices, 2011, Kanpur, India
Abstract
Ultrathin HfTaOx gate dielectric has been deposited on Si0.81Ge0.19 by RF co-sputtering of HfO2 and Ta2O5 targets. X-ray photoelectron spectroscopic (XPS) analyses indicate an interfacial layer containing GeOx, Hf silicate, SiOx (layer of Hf- Si-Ge-O) formation during deposition of HfTaOx. No evidence of Ta-silicate or Ta incorporation was found at the interface. X-ray diffraction (GIXRD) measurements show that as-deposited HfTaOx films are amorphous; however, the crystallization temperature of HfTaOx film is found to increase significantly after annealing beyond 500 °C (for 5 min) along with the incorporation of Ta (with 18% Ta). It has been found that HfTaOx gate dielectric on Si0.81Ge0.19 exhibit excellent electrical properties with low interface state density (~6.0×1011 cm-2eV-1) and hysteresis voltage (<70 mV). Charge trapping/detrapping behavior of the gate stacks has been studied under constant voltage stressing and the degradation mechanism of the dielectrics has been studied in detail.
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S. Mallik, C. Mahata, M. K. Hota, C. K. Sarkar, C. K. Maiti, "Effects of constant voltage stressing on HfTaOx/SiGe gate stack", Proc. SPIE 8549, 16th International Workshop on Physics of Semiconductor Devices, 854925 (15 October 2012); doi: 10.1117/12.926999; https://doi.org/10.1117/12.926999
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KEYWORDS
Silicon

Dielectrics

Germanium

Interfaces

Tantalum

Crystals

Oxides

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