QUALITY EVALUATION METHOD FOR LAMINATE HAVING PROTECTIVE LAYER ON SURFACE OF OXIDE SEMICONDUCTOR THIN FILM AND QUALITY CONTROL METHOD FOR OXIDE SEMICONDUCTOR THIN FILM
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Abstract
Provided is a method for simply evaluating defects caused in interface states in oxide semiconductor thin films and protective films in TFTs having protective films formed on the surface of oxide semiconductor thin films without actually measuring the characteristics of the same.
This evaluation method evaluates defects caused in the interface states by measuring electron states in the oxide semiconductor thin film by a contact method or noncontact method. The defects caused in the interface states are any of the following (1)-(3).
- (1) Threshold value voltage (Vth,) when a positive bias is applied to the thin-film transistor
- (2) Difference in threshold value voltage (ΔVth) before and after applying the positive bias to the thin-film transistor
- (3) Threshold value during the first measurement when a plurality of measurements is made of the threshold value voltage when a positive bias is applied to the thin-film transistor.
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Citations
25 Claims
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1-11. -11. (canceled)
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12. A quality evaluation method of a laminate including a protective film on a surface of an oxide semiconductor thin film,
wherein a defect caused by an interface state between the oxide semiconductor thin film and the protective film is evaluated by measuring a sheet resistance or a specific resistance of the oxide semiconductor thin film by a contact method or a noncontact method.
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18. A quality evaluation method of a laminate for evaluating a thin film transistor, wherein when a defect caused by an interface state between the oxide semiconductor thin film and the protective film is measured by a noncontact method based on an electronic state of the oxide semiconductor thin film of the laminate comprising a protective film thereon, the measurement includes;
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(i) irradiating the laminate with excitation light and a microwave, measuring maximum of a reflected wave of the microwave from the oxide semiconductor thin film, the maximum being varied by irradiation of the excitation light, and then stopping irradiation of the excitation light, and measuring temporal change in reflectance of the reflected wave of the microwave from the oxide semiconductor thin film after stopping irradiation of the excitation light, and (ii) calculating a parameter corresponding to slow decay, the slow decay being observed after stopping irradiation of the excitation light, from the temporal change in reflectance to evaluate the electronic state of the oxide semiconductor thin film. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
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Specification