Highly Stable Short Channel Ultrathin Atomic Layer Deposited Indium Zinc Oxide Thin Film Transistors With Excellent Electrical Characteristics

The high-performance atomic layer deposited (ALD) ultrathin (~2 nm) amorphous InZnO ( {a} -IZO, indium: Zinc ≈ 6:4) channel thin-film transistors (TFTs) with a short channel length ( \text{L}_{\mathbf {\textit {ch}}} ) of 50 nm were presented. Furthermore, the gate stability was evaluated using temperature-dependent positive-bias stress (PBS) tests for the IZO TFTs up to 3.5 MV/cm. The short channel TFTs exhibited excellent electrical characteristics, with high \text{I}_{\mathbf {\textit {on}}} exceeding 360~\mu \text{A} / \mu \text{m} (@ \text{V}_{\mathbf {G}} = 2V), and an optimized threshold voltage ( \text{V}_{\mathbf {\textit {th}}} ) of ~ 0.11 V. In particular, the ultra-low drain-induced barrier lowering (DIBL) performance of 16 mV/V was presented and matched with technology computer aided design (TCAD) estimation. The activation energy of device degradation was extracted to better understand the mechanism. The extracted high field effect channel mobility ( \mu _{\mathbf {\textit {FE}}} ) of 43.6 cm ^{\mathbf {{2}}} /V-s in conjunction with the low \text{V}_{\mathbf {\textit {th}}} shifts of 12.4 mV (@ 3.5 MV/cm; \text{V}_{\mathbf {\textit {th}}} +2V) for 5000s PBS test at 25^{\mathbf {o}} C exhibited the excellent performances combining channel mobility and gate stability reported for oxide semiconductor TFT.