Dresden 2014 – scientific programme
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DF: Fachverband Dielektrische Festkörper
DF 9: Poster Session DF
DF 9.14: Poster
Tuesday, April 1, 2014, 18:30–20:00, P1
Frequency Dispersions of Accumulation Capacitances of Metal/n-VO2/SiO2/p-Si Capacitors — Varun John1, •Lei Zhang1, Danilo Bürger1, Ilona Skorupa2, Oliver Schmidt3, and Heidemarie Schmidt1 — 1Material Systems for Nanoelectronics, Chemnitz University of Technology — 2Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf — 3Institute for Integrative Nanosciences, IFW Dresden
Admittance measurements have been performed on Al/n-VO_2/SiO_2/p-Si capacitors with different VO_2 thicknesses and on Al/SiO_2/p-Si reference MOS capacitors. The MOS capacitor with an extra VO_2 layer shows an anomalous frequency dependent capacitance for -7V accumulation bias due to bulk traps introduced to the SiO_2 layer during the growth of VO_2 by PLD[1]. The accumulation capacitance varies from a large value at the low AC test bias frequency of 1kHz to a value of 0.05 μF at the frequency of 1MHz which corresponds to the capacitance of the 80nm thick SiO_2 layer. The accumulation capacitance has a direct relation to the VO_2 layer thickness. The capacitance vs frequency curves of the Al/n-VO_2/SiO_2/p-Si capacitors are modeled using a distributed circuit model taking into account the admittance arising from the change in occupancy of bulk traps in SiO_2[2]. The position dependent density and the time constant of the traps have been obtained from the best fit parameters in the simulations. [1] György J. Kovács, et al., Appl. Phys. 109, 063708 (2011). [2] Y. Yuan, et al., IEEE Trans. on Electron Devices, 59, 2100-06 (2012).