METHOD FOR EXTRACTING SUBGAP DENSITY OF STATES OF AMORPHOUS OXIDE SEMICONDUCTOR THIN-FILM TRANSISTOR AND APPARATUS THEREOF

摘要

Disclosed is a method for extracting state density in a band gap of an amorphous oxide semiconductor thin film transistor and a device for the same. The method for extracting state density in a band gap of an amorphous oxide semiconductor thin film transistor according to an embodiment of the present invention includes a step of measuring a drain current according to a gate voltage of the thin film transistor; a step of calculating an ideality factor according to the gate voltage by using the measured drain current; a step of differentiating the calculated ideality factor and obtaining a capacitance within a channel based on the differentiated ideality factor; and a step of extracting the state density within the band gap of the thin film transistor based on the obtained capacitance within the cannel. The step of calculating the ideality factor comprises: calculating the ideality factor based on the drain current which is less than or equal to a threshold voltage among the measured drain current so that the state density in the band gap can be extracted without a complex modification. The ideality factor is differentiated so that the accurate state density in the band gap, which is independent to the threshold voltage and is not influenced from heat, light, or temperature, can be extracted. [Reference numerals] (AA) START; (BB) END; (S310) Measuring drain current according to gate voltage; (S320) Calculating an ideal coefficient according to the gate voltage by using the measured drain current; (S330) Differentiating the calculated ideal coefficient; (S340) Obtaining capacitance in a channel based on the differentiated ideal coefficient; (S350) Extracting status density in a band gap based on the capacitance in the obtained channel