PECVD Silicon Oxynitride as Insulator for MDMO-PPV Thin-Film Transistors


  • Marco R. Cavallari
  • Katia F. Albertin
  • Gerson dos Santos
  • Carlos A. S. Ramos
  • Inés Pereyra
  • Fernando J. Fonseca
  • Adnei M. de Andrade



organic transistor, MDMO-PPV, hole mobility, SiOxNy, surface treatment


We demonstrate that PECVD SiOxNy with good dielectric properties can replace thermally grown SiO2 in Organic Thin-Film Transistors (OTFT) applications. It can be used on ITO-covered glass or even flexible substrates. Poly [2-methoxy-5-(3’,7’-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) is used as the active layer, due to its wide range of applications such as bulk heterojunction solar cells, light-emitting diodes and light-emitting transistors.We show that charge carrier mobility can be at least two times higher for MDMO-PPV on silicon oxynitride than silicon dioxide, μh 1.1x10-4 cm2/Vs. MDMO-PPV spun from solvents such as chloroform and toluene provide comparable TFT performance on SiOxNy. Preliminary studies of devices with hexamethyldisilazane-treated SiO2 demonstrate that performance can be further improved by the choice of a proper surface treatment.