Enhanced structural and electrical features of amorphous InGaZnO thin film transistors via a heavy Kr gas process

• Oxide TFTs with a-IGZO channel layer has been fabricated using different sputtering process using a heavy Kr sputtering gas.
• High density and low roughness IGZO channel layer by sputtering heaver gas were observed by x-ray reflectivity (XRR) and AFM.
• The stability of oxide TFTs was controlled by the amount of oxygen vacancy in IGZO channel layer.

We report the influence of a heavy Kr gas sputtering process on the electrical and structural features of amorphous indium–gallium–zinc-oxide (a-IGZO) thin film transistors (TFTs). Electrical observation revealed effective reduction of threshold voltage shifts by adapting a simple sputtering process with Kr gas during growth of a-IGZO TFTs. In addition, the application of Kr-gas resulted in a reduction of oxygen vacancies associated with defect sites in the a-IGZO active channel layer. Structural analyses including atomic force microscopy, X-ray reflectivity, Auger electron spectroscopy, and X-ray photoelectron spectroscopy depth profiling were carried out, along with electrical bias stability tests that convincingly confirm progress of heavy Kr gas process-induced features.