Dresden 2014 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 23: Quantum wires: Transport properties (with TT)
HL 23.7: Talk
Monday, March 31, 2014, 17:30–17:45, POT 006
Investigation of top-gated InAs nanowires with HfO2 dielectric — •Marion Rosien1,2, Torsten Rieger1,2, Sebastian Heedt1,2, Torsten Jörres1,2, Thomas Schäpers1,2, Detlev Grützmacher1,2, and Mihail Ion Lepsa1,2 — 1Peter Grünberg Institute - 9, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — 2JARA-Fundamentals of Future Information Technology
Electrical characteristics of top-gated InAs nanowire field effect transistors (FETs) with HfO2 high-k gate dielectric are presented. The nanowires with diameters of about 60 to 80 nm are grown by molecular beam epitaxy (MBE) and coated with HfO2. The HfO2 is deposited ex-situ by atomic layer deposition (ALD), which benefits from a high conformity and a good thickness control. To investigate the impact of the gate, the oxide thickness is varied between 2 and 8 nm. Transfer times between the MBE and ALD are kept as short as possible to avoid any contamination. The nanowires are individually contacted by Ti/Au electrodes. The HfO2 acts as an omega shaped gate dielectric with Ti/Au gate metal. The quality of the oxide and the interface between the nanowire and the dielectric is analyzed by DC electrical measurements of the FETs. In order to derive transport parameters from the measurements, the capacitance of the top gate is simulated for each individual nanowire. The carrier mobility and concentration, peak transconductance and the on/off ratio are presented and discussed.