Characteristics of ALD‐ZnO Thin Film Transistor Using H₂O and H₂O₂ as Oxygen Sources

Abstract

Abstract ZnO thin films are deposited by atomic layer deposition (ALD) using diethylzinc as the Zn source and H 2 O and H 2 O 2 as oxygen sources. The oxidant‐ and temperature‐dependent electrical properties and growth characteristics are systematically investigated. Materials analysis results suggest that H 2 O 2 provides an oxygen‐rich environment so that the oxygen vacancies ( V O ) is suppressed, implying a lower carrier concentration and a higher resistivity. The lower growth rate makes it possible for the ZnO thin films to grow along the lower surface energy direction of <002>, leading to a lower Hall mobility. Furthermore, the ZnO semiconductor is integrated into thin film transistor (TFT) devices and the electrical properties are analyzed. The TFT with H 2 O 2 ‐ZnO grown at 150 °C shows good electrical properties, such as a high field‐effect mobility of 10.7 cm 2 V –1 s –1 , a high ratio I on / I off of 2 × 10 7 , a sharp subthreshold swing of 0.25 V dec –1 , and a low trapping state ( N trap ) of 2.77 × 10 12 eV –1 cm –2 , which provides a new pathway to optimize the performance of metal‐oxide electronics.