Based on a kinetic model involving oxidant diffusion and an oxidation‐reduction reaction, a 3‐parameter equation is derived relating the change in the concentration of thermally induced carrier donors in common metal‐oxide semiconductors (such as indium–gallium–zinc oxide and indium–tin–zinc oxide) to heat‐treatment time. The change in the concentration of such donors is characterized by measuring the shift in the turn‐on voltage of a thin‐film transistor subjected to heat treatments in different atmospheres for different durations. The model parameters are extracted using optimal curve‐fitting techniques, leading to the determination of relevant activation energies from the temperature dependence of the extracted parameters. The proposed model is found to be applicable to metal‐oxide semiconductors of different compositions. It is discovered that the generation of donors in a non‐oxidizing atmosphere is largely suppressed at a temperature below 250 °C, but the effective annihilation of the donors spans over a wider temperature range in an oxidizing atmosphere.

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Mobile charge carriers can be generated in indium‐tinzinc oxide (ITZO) covered with a silicon oxide layer when subjected to an oxygen plasma treatment. The resulting ‍resistivity is sensitive to the thickness of the cover oxide, the plasma excitation power, and the treatment time. With 280 ‍nm of cover oxide and 10 mins of treatment, a low resistivity of 1.2 mΩ∙cm can be obtained in a plasma biased ‍with a radio frequency excitation power of 100 W and an inductively coupled plasma excitation power of 2000 W. ‍The treatment has been deployed to form the source/drain regions of a self‐aligned, top‐gate ITZO thin‐film ‍transistor.