Improvement of the photo-bias stability of the Zn-Sn-O field effect transistors by an ozone treatment

Highly improved negative bias illumination stress stability was achieved in a Zn-Sn-O field effect transistor after an ozone (O-3) treatment. The untreated ZTO FET exhibited a huge negative threshold voltage shift of 4.2 V but the O-3 treated device exhibited superior stability under NBIS conditions: the V-th value of the O-3 treated ZTO FET for 600 s showed almost no change (Delta V-th = 0.07 V) under the same NBIS. The improvement in NBIS stability of the O-3 treated ZTO FETs was attributed to the lower oxygen vacancy concentration and retarded desorption of adsorbed oxygen under photon irradiation by the O-3 treatment.