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Active and Passive Electronic Components
Volume 2012 (2012), Article ID 729328, 6 pages
Research Article

Gate Stack Engineering and Thermal Treatment on Electrical and Interfacial Properties of Ti/Pt/HfO2/InAs pMOS Capacitors

Department of Electrical Engineering, National Central University, Chungli 32001, Taiwan

Received 16 March 2012; Revised 6 June 2012; Accepted 11 June 2012

Academic Editor: Yeong-Her Wang

Copyright © 2012 Chung-Yen Chien et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Effects of gate stack engineering and thermal treatment on electrical and interfacial properties of Ti/Pt/HfO2/InAs metal insulator semiconductor (MIS) capacitors were systematically evaluated in terms of transmission electron microscopy, energy dispersive X-ray spectroscopy, current-voltage, and capacitance-voltage characterizations. A 10 nm thick Pt metal effectively suppresses the formation of interfacial oxide, TiO2, between the Ti gate and HfO2 gate dielectric layer, enhancing the gate modulation on the surface potential of InAs. An in situ HfO2 deposition onto the n-InAs channel with an interfacial layer (IL) of one-monolayer InP followed by a 300°C post-metal-anneal produces a high-quality HfO2/InAs interface and thus unravels the annoying Fermi-level pinning, which is evidenced by the distinct capacitance dips in the high-/low-frequency C-V characteristics. The interface trap states could be further suppressed by replacing the InP IL by an As-rich InAs, which is substantiated by a gate leakage reduction and a steep voltage-dependent depletion capacitance.