Comparative Study of Indium Oxide Films for High-Mobility TFTs: ALD, PLD and Solution Process

Abstract

Deposition of indium oxide base films for high-mobility thin film transistors (TFTs) has been an important part in the implementation of high-resolution and high-frequency display back panels. In this study, three types of In₂O₃ (InO) films have been fabricated for TFTs using atomic layer deposition (ALD), pulsed laser deposition (PLD), and solution process, respectively. ALD-derived InO films show controllable grain formation and optimized TFTs show the field effect mobility of ≈100 cm² V⁻¹s⁻¹ in both the conventional transistor measurements and critical four-probe measurements, reaching the level of low-temperature polycrystalline silicon (LTPS). Combined spectroscopy investigations show that the ALD-derived InO film features advantages as compared to those of the PLD-deposited and solution-processed InO film in providing a smoother surface morphology, good crystallinity, and more orderly atomic growth mode. Moreover, the bias-stress stability of ALD-derived TFTs can be improved with further passivation.