Improvement in performance of indium gallium oxide thin film transistor via oxygen mediated crystallization at a low temperature of 200 °C

We report the fabrication of high-performance polycrystalline indium gallium oxide (IGO) thin film transistors (TFTs) at a low temperature of 200 degrees C. Growth of a highly aligned cubic phase with a bixbyite structure was accelerated at a certain proportion of oxygen plasma density during deposition of the IGO thin film, which leads to outstanding electrical characteristics. The resulting polycrystalline IGO TFT exhibited a high field-effect mobility of 56.0 cm(2)/V, a threshold voltage (V-TH) of 0.10 V, a low subthreshold gate swing of 0.10 V/decade, and a current modulation ratio of >10(8). Moreover, the crystalline IGO TFTs have highly stable behaviors with a small V-TH shift of +0.8 and -1.0 V against a positive bias stress (V-GS,V-ST -V-TH = 20 V) and negative bias illumination stress (V-GS,V-ST -V-TH = -20 V) for 3,600 s, which is attributed to the high quality of the bixbyite crystalline structure.

Automated summary

In this study, high-performance polycrystalline IGO TFTs were successfully fabricated at a low temperature with outstanding electrical characteristics and high stability. The density of oxygen plasma plays a crucial role in the crystalline quality of the IGO thin film.