Engineering density of semiconductor-dielectric interface states to modulate threshold voltage in OFETs

Publication Type:

Journal Article

Source:

IEEE Trans. Electron Devices, ieeexplore.ieee.org, Volume 53, Issue 1, p.9-13 (2006)

ISBN:

0018-9383

Keywords:

2006, 2013 and earlier, Atom optics, atomic force microscopy, chemical treatment, Chemicals, dielectric materials, Dielectrics, electron traps, engineering density, field effect transistors, gate dielectric layer, interface states, OFETs, optical microscopy, organic compounds, organic polymer gate dielectric, oxygen plasma treatment, parylene, Pentacene, pentacene organic field-effect transistors, Plasma chemistry, plasma materials processing, Polymers, semiconductor-dielectric interface states, semiconductor-insulator boundaries, surface treatment, thin-film transistors (TFTs), Threshold voltage, threshold voltage modulation, threshold-voltage control, trap-introduced charges

Abstract:

Threshold-voltage control is critical to the further development of pentacene organic field-effect transistors (OFETs). In this paper, we
demonstrate that the threshold voltage can be tuned through chemical
treatment of the gate dielectric layer. We show that oxygen plasma
treatment of an organic polymer gate dielectric, parylene, introduces
traps at the semiconductor-dielectric interface that strongly affect the
OFET performance. Atomic force microscopy, optical microscopy using
crossed-polarizers, and current-voltage and capacitance-voltage
characterization were performed on treated and untreated devices. A model
is presented to account for the effects of trap-introduced charges, both
1) fixed charges (2.0×10-6 C/cm2) that shift the threshold voltage from