(Invited) Illumination Light Wavelength Effects on Double-Gate a-IGZO Thin Film Transistor with Top-Gate-to-Source/Drain Offset Structure

Electrical properties of the double-gate amorphous In-Ga-Zn-O thin film transistor with the top-gate-to-source/drain offset structure were investigated in dark and under visible and UV light illumination conditions. With the increase of the band gap energy of the incident light, the amount of charge carries generated in the semiconductor channel layer was increased, which enhanced the field effect mobility and increased the leakage current. At the same time, defects were created, which deteriorated the threshold voltage and subthreshold slope. For the top-gate thin film transistor, the UV illumination seriously deteriorated all device characteristics except the leakage current because of the reduction of oxygen vacancies. The performance of the double-gate thin film transistor was dominated by the bottom-gate transistor. Light illumination effects in the bottom- and double-gate transistors were similar but much less serious than those of the top-gate transistor. The understanding of the wavelength-dependent light illumination effect is critical to double-gate thin film transistor applications.