Ambient Pressure Dependent Characteristics of F16CuPc Transistors with Polyimide and SiO2 Gate Insulators

Abstract

N-channel organic field effect transistors (FETs) with F16CuPc/SiO2(300 nm)/Si and F16CuPc(20 nm)/Polyimide(320 nm)/Si structures were fabricated, and the transistor electrical characteristics measured in the air and in a vacuum at a pressure below 1.3 Pa were compared. The threshold voltage Vth and the mobility μ of the transistor with the SiO2 gate insulator are strongly dependent of the ambient pressure during the measurements, while those of the transistor with the Polyimide gate insulator are nearly independent of the ambient pressure during the electrical measurements. The change of the transistor characteristics on the ambient pressure might be attributed to the absorption and desorption of some negatively charged chemical species on the transistor channel interface region.