Breaking the Trade-Off Between Mobility and On–Off Ratio in Oxide Transistors

Amorphous oxide semiconductors (AOS) are pivotal for next-generation electronics due to their high electron mobility and excellent optical properties. However, In₂O₃, a key material in this family, encounters significant challenges in balancing high mobility and effective switching as its thickness is scaled down to nanometer dimensions. The high electron density in ultra-thin In₂O₃ hinders its ability to turn off effectively, leading to a critical trade-off between mobility and the on-current (I_on)/off-current (I_off) ratio. This study introduces a mild CF₄ plasma doping technique that effectively reduces electron density in 10 nm In₂O₃ at a low processing temperature of 70 °C, achieving a high mobility of 104 cm² V⁻¹ s⁻¹ and an I_on/I_off ratio exceeding 10⁸. A subsequent low-temperature post-annealing further improves the critical reliability and stability of CF₄-doped In₂O₃ without raising the thermal budget, making this technique suitable for monolithic three-dimensional (3D) integration. Additionally, its application is demonstrated in In₂O₃ depletion-load inverters, highlighting its potential for advanced logic circuits and broader electronic and optoelectronic applications.