High-Performance ALD IGZO Field-Effect Transistors with Ultralow Subthreshold Swing

Subthreshold swing and contact resistance are key parameters for scaling transistors. This work fabricated high-performance IGZO-based transistors by incorporating an ITO contact interlayer. The IGZO channel was in situ grown using atomic layer deposition on a 6 nm HfLaO gate dielectric, resulting in devices with outstanding mobility of $27 \mathrm{~cm}^{2} / \mathrm{V} \cdot \mathrm{s}$. We systematically investigated the effect of channel length on device performance and evaluated the role of the ITO interlayer in reducing contact resistance. The inclusion of the ITO interlayer significantly reduced the contact resistance to $165 \Omega \cdot \mu \mathrm{~m}$. Notably, for a 100 nm channel length, the transistors exhibited a subthreshold swing of $62 \mathrm{mV} /$ dec, a transconductance of 351 $\mu \mathrm{S} / \mu \mathrm{m}$, and a high on-state current of $548.6 \mu \mathrm{~A} / \mu \mathrm{m}$ at a drain-source voltage of 1 V. These results underscore the significant potential of IGZO transistors for future three-dimensional stacked memory applications, offering promising performance for high-density, low-power electronic devices.