Improved electrical characteristics of zinc oxide thin-film with fluorine passivation

Thin-film transistors fabricated on fluorinated zinc oxide have been found to exhibit improved electrical characteristics. The dependence of the extent of the improvement on the amount of fluorine is investigated. At a fluorine concentration of ~10²⁰/cm³, transistors with a relatively high field-effect mobility of ~71cm²/Vs, a relatively low pseudo sub-threshold slope of 0.18V/decade and improved reliability have been realized. The enhancement is attributed to the passivation of carrier traps by fluorine. Fluorine concentration in excess of ~10²⁰/cm³ is found to degrade transistor performance.