Performance improvement of pentacene-based organic thin-film transistor with HfO2 gate dielectrics treated by CF4 plasma

Abstract

Fluorine incorporation into the HfO2 gate dielectrics by post CF4 plasma treatment in an inductively coupled plasma chamber was proposed to improve gate leakage current and modify surface property for low-temperature fabrication. During the whole process, the temperature is controlled below 150 degrees C. The low-leakage HfO2 dielectric treated by CF4 plasma was characterized and then utilized in pentacene-based OTFTs. After CF4 plasma treatment, the gate leakage and field effect mobility were effectively improved. By integrating high-k HfO2 by CF4 plasma treatment and HMDS evaporation treatment, a low operating voltage (-4V), low threshold voltage (-1.12V), a low subthreshold swing (266 mV/decade), a field-effect mobility (0.029cm(2)/Vs) and an on/off current ratio (>10(4)) were obtained.