Highly stable low-temperature aqueous solution-processed oxide thin-film transistors by the hydrogen injection and oxidation method

We demonstrate the high stability of low-temperature aqueous solution-processed In-Ga-Zn-O (IGZO) thin-film transistors (TFTs) by application of the hydrogen injection and oxidation (HIO) method at annealing temperatures as low as 250 °C. Solution processing is considered an innovative cost-reduction method for various electronics products; however, solution-processed TFTs for device applications have not yet been realized due to poor TFT performance, such as low mobility, a large subthreshold swing, and instability. Using the HIO method, improvement in the TFT characteristics was confirmed in terms of the mobility and electrical stability, compared to that for conventional solution-processed IGZO TFTs. The TFTs processed with the HIO method exhibited an improvement in stability by more than 10 V under positive bias stress and 1.5 V under negative bias stress. The HIO method is a simple process to enhance the quality of solution-processed oxide films by the decomposition of residual species using a reduction reaction. It is demonstrated to be an inexpensive and effective means to realize solution-processed oxide semiconductors for device applications.