Single-crystalline In₂O₃ has a Hall mobility as high as 160 cm²V⁻¹s⁻¹, which makes amorphous (a-) or polycrystalline (poly-) InO_x a potential material for enhancing the μ_FE of OS TFTs. However, undoped InOx thin films is known as a degenerate semiconductor with high background electron density of over 10²⁰ cm^-3, which is attributed to the presence of native defects, such as oxygen vacancies, making them unsuitable for a channel material of OS TFTs.

In this presentation, nondegenerate hydrogen-doped polycrystalline InO_x (poly-InO_x:H) thin films were successfully prepared by low-temperature solid phase crystallization (SPC). A degenerate amorphous InO_x:H thin film was deposited by sputtering in Ar, O₂, and H₂ gases, and an amorphous to polycrystalline phase transition (SPC) of the film was achieved after PDA at more than 175 °C. By PDA at 250 °C in air, a nondegenerate poly-InO_x:H film could be obtained with a carrier density as low as 2.4 × 10¹⁷ cm⁻³, which is approximately three orders of magnitude lower than that of the initial a-InO_x:H film. The TFTs with a 50 nm thick nondegenerate poly-InO_x:H channel could be fully depleted by a gate electric field. A maximum μ_FE of 125.7 cm²V⁻¹s⁻¹ was exhibited by the TFT with the poly-InO_x:H channel. The use of a nondegenerate poly-InO_x:H film is a promising approach to boost the μ_FE of OS TFTs.