Organic small molecule field-effect transistors with Cytop™ gate dielectric: Eliminating gate bias stress effects

Abstract

Organic field-effect transistors with unprecedented resistance against gate bias stress are described. The single crystal and thin-film transistors employ the organic gate dielectric Cytop™. This fluoropolymer is highly water repellent and shows a remarkable electrical breakdown strength. The single crystal transistors are consistently of very high electrical quality: near zero onset, very steep subthreshold swing [average: $1.3\mathrm{nF}\mathrm{V}∕\left(\text{decade}{\mathrm{cm}}^2\right)$ ] and negligible current hysteresis. Furthermore, extended gate bias stress only leads to marginal changes in the transfer characteristics. It appears that there is no conceptual limitation for the stability of organic semiconductors in contrast to hydrogenated amorphous silicon.