Pulsed plasma polymerized dichlorotetramethyldisiloxane high-k gate dielectrics for polymer field-effect transistors

Abstract

Polymerized dichlorotetramethyldisiloxane (DCTMDS) films deposited by radio-frequency pulsed plasma polymerization (PPP) demonstrated very high dielectric constants for a polymer-based system, in the range of 7–10. The high dielectric constants of PPP DCTMDS films are due to the high polarizability of the DCTMDS monomer. The pulsed plasma duty cycle (on/off) resulted in slightly higher dielectric constant DCTMDS films for higher duty cycles. The variation of dielectric constants does not show any trend with varying film thicknesses, indicating that the thickness of the deposited films is not significant for controlling permittivity. Postdeposition annealing in a certain temperature range improves the electrical integrity of PPP DCTMDS films, but temperatures that are too high induce even higher leakage than the samples with no heat treatment. An optimal annealing temperature was identified to be in the range of 150–200 °C. Samples annealed within this temperature window have low leakage current densities below 0.1pA∕μm2 at 10 V for film thicknesses about 100 nm. Poly(3-hexythiophene) polymer field-effect transistors (PFETs) using PPP DCTMDS gate dielectric films were fabricated and tested. Due to the high dielectric constants of PPP DCTMDS, these PFETs possess high gate capacitance and operate at low voltage.

Temporal Evolution of an Electron-Free Afterglow in the Pulsed Plasma Polymerisation of Acrylic Acid

“…The highly adherent pinhole-free deposits may be readily formed on surfaces from plasmas struck in a range of volatile organic compounds to achieve many different types of chemistry. , For most organic compounds with a significant vapor pressure under vacuum, it is possible to strike a discharge in the pure monomer, and for low-input powers (a few Watts), the monomer functionality can be retained in the deposit . Through important but empirical research, it has been shown that in low-power continuous-wave (CW) radio-frequency (RF) plasmas, reduced monomer fragmentation in the discharge leads to high functional group retention in the films. − In a refinement of the technique, it has been found that for a host of different monomers good control over the surface chemistry can be achieved by pulsing the RF power, − with long off periods t off (milliseconds) and short on periods t on (in the hundreds of microseconds range). The short duration of the on period is sufficient to produce radicals and charged species in the plasma necessary for the polymerization to proceed (primarily in the off period).…”

“…6 Through important but empirical research, it has been shown that in low-power continuous-wave (CW) radio-frequency (RF) plasmas, reduced monomer fragmentation in the discharge leads to high functional group retention in the films. [6][7][8][9][10] In a refinement of the technique, it has been found that for a host of different monomers good control over the surface chemistry can be achieved by pulsing the RF power, [11][12][13][14][15][16][17][18][19] with long off periods t off (milliseconds) and short on periods t on (in the hundreds of microseconds range). The short duration of the on period is sufficient to produce radicals and charged species in the plasma necessary for the polymerization to proceed (primarily in the off period).…”