Improvement in the bias stability of tin oxide thin-film transistors by hafnium doping

Abstract

Thin-film transistors (TFTs) were fabricated with hafnium doped tin oxide (HTO) channels, and the effects of Hf content on the device performance of SnO x based TFTs was investigated. HTO TFTs exhibit improved electrical properties with increased field effect mobility and decreased subthreshold swing. We also investigated the influence of hafnium doping on bias stability in SnO x TFTs. HTO TFTs exhibited turn-on voltage (V ON) shifts of + 7 V for positive stress bias, compared with + 18 V for SnO x TFTs. The improvement in the V ON shift may be due to reduction in total trap density resulting from the suppression of defects related oxidation state of the Sn ion caused by the high binding energies of Hf ions.