In-line Process Monitoring for Amorphous Oxide Semiconductor TFT Fabrication using Microwave-detected Photoconductivity Decay Technique

We have investigated the microwave-detected photoconductivity responses from the amorphous In–Ga–Zn–O (a-IGZO) thin films. The time constant extracted by the slope of the slow part of the reflectivity signals are correlated with TFT performances. We have evaluated the influences of the sputtering conditions on the quality of a-IGZO thin film, as well as the influences of gate insulation films and annealing conditions, by comparing the TFT characteristics with the microwave photoconductivity decay (μ-PCD). It is concluded that the μ-PCD is a promising method for in-line process monitoring for the IGZO-TFTs fabrication. key words: oxide semiconductor, thin film transistor, microwave-detected photoconductivity decay, in-line process monitoring