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 (O3) treatment. The untreated ZTO FET exhibited a huge negative threshold voltage shift of 4.2 V but the O3 treated device exhibited superior stability under NBIS conditions: the Vth value of the O3 treated ZTO FET for 600 s showed almost no change (ΔVth = −0.07 V) under the same NBIS. The improvement in NBIS stability of the O3 treated ZTO FETs was attributed to the lower oxygen vacancy concentration and retarded desorption of adsorbed oxygen under photon irradiation by the O3 treatment.