High-Performance Atomic-Layer-Deposited Indium Oxide 3-D Transistors and Integrated Circuits for Monolithic 3-D Integration.

In this work, we report the experimental demonstration of In2O3 3-D transistors coated on fin structures and integrated circuits by a back-end-of-line (BEOL) compatible atomic layer deposition (ALD) process. High-performance planar back-gate In2O3 transistors with high mobility of 113 cm2/ $\text{V}\cdot \text{s}$ and high maximum drain current (${I}_{\rm D}$) of 2.5 mA/ $\mu \text{m}$ are achieved by channel thickness engineering and postdeposition annealing. The high-performance ALD In2O3-based zero- ${V}_{\rm GS}$ -load inverter is demonstrated with a maximum voltage gain of 38 V/V and a minimum supply voltage (${V}_{\rm DD}$) down to 0.5 V. Top-gate indium oxide (In2O3) transistors by low-temperature ALD of both gate insulator and channel semiconductor are also demonstrated with ${I}_{\rm D}$ of $570~\mu \text{A}/\mu \text{m}$ and low subthreshold slope (SS) down to 84.6 mV/decade. ALD In2O3 3-D Fin transistors with the top-gate structure are then demonstrated, benefiting from the conformal deposition capability of ALD. These results suggest that ALD oxide semiconductors and devices have unique advantages and are promising toward BEOL-compatible monolithic 3-D integration for 3-D integrated circuits. [ABSTRACT FROM AUTHOR]