Lateral Profiling of Defects and Charges in Oxide Semiconductor Channel Thin-Film Transistors

The lateral distributions of free carriers and defects in a channel of top gate In-Ga-Zn-O thin-film transistors were extracted using a single pulse charge pumping method. A square pulse was applied to the gate, while the charge transport current was monitored at the source-drain. A transmission line model was used to confirm the charging mechanism and extract the effective charge length. The time dependence of the trapped charge density was determined by comparing the charging and discharging transient characteristics. The lateral profiles of the free carriers and defects were decoupled successfully using the time dependence of the effective charge length, free charges, and trapped charges.