An experimental investigation of the surface potential in ferroelectric P(VDF-TrFE) FETs

In this paper we report the fabrication and detailed electrical characterization of a ferroelectric transistor (Fe-FET) aiming at the extraction of its physical threshold voltage. The investigated transistors are fabricated on doped bulk silicon with a gate stack including 10 nm silicon dioxide, 40 nm P(VDF-TrFE) and Au. Based on capacitive measurements, a capacitive divider circuit and a long-channel MOSFET model, we subsequently extract the surface potential psi(S) dependence on the gate voltage and the physical threshold voltage. The experimental data suggest a more abrupt d psi(S)/dV(g) slope, compared with a conventional transistor. A hysteretic behavior, due to the polarization of the P(VDF-TrFE), is observed in the psi(S)-V-g characteristics. (C) 2009 Elsevier B.V. All rights reserved.