Characterization of MIS structures and thin film transistors using RF-sputtered HfO2/HIZO layers

MIS structures using HfO2 and HIZO layers, both deposited by room temperature RF magnetron sputtering are fabricated for TFTs application and characterized using capacitance-voltage. The relative dielectric constant obtained at 1 kHz was 11, the charge carrier concentration of the HIZO was in the range of (2-3) × 1018 cm− 3 and the interface trap density at flat band was smaller than 2 × 1012 cm− 2. The critical electric field of the HfO2 layer was higher than 5 × 105 V/cm, with a current density in the operating voltage range below 4 × 10− 8 A/cm2. The hysteresis and bias stress behavior of RF-sputtered HfO2/HIZO MIS structures is presented. Fabricated HfO2/HIZO TFTs worked in the operation voltage range below 8 V.