Dry etch damage and recovery of gallium indium zinc oxide thin-film transistors with etch-back structures

Abstract

We studied the degradation and recovery of gallium indium zinc oxide (GIZO) thin-film transistors (TFTs) with etch-back (EB) structures during the fabrication process. EB GIZO TFTs were degraded by a source/drain dry etch process that formed a conductive surface layer. Their switching performance was recovered using an O2 ashing process that oxidized the conductive surface layer. In addition, a wet etch of the backside of the GIZO recovered the performance of the GIZO TFTs. EB GIZO TFTs with a field-effect mobility of 14.5cm2V−1s−1 and a subthreshold swing of 0.1V/dec were obtained without plasma treatment.