Electrical behavior of zinc oxide layers grown by low temperature atomic layer deposition

We report on the electrical properties of thin film transistors based on zinc oxide (ZnO) layers grown by low temperature (100–170°C) atomic layer deposition. As evidenced through Hall effect measurements, a drastic decrease of the carrier concentration occurred for ZnO films grown at 100°C. Time of flight–secondary ions mass spectroscopy analysis revealed that this decrease is associated with an increase of the hydroxide groups in the ZnO layer which suppressed oxygen vacancy formation. Transistors fabricated from ZnO films grown at 100°C exhibit a high Ion∕Ioff ratio (∼107) and an encouraging intrinsic channel mobility (∼1cm2∕Vs).