First Demonstration of Atomic-Layer-Deposited BEOL-Compatible In2O3 3D Fin Transistors and Integrated Circuits: High Mobility of 113 cm2/V•s, Maximum Drain Current of 2.5 mA/μm and Maximum Voltage Gain of 38 V/V in In2O3 Inverter

In this work, we report the first demonstration of In
2
O
3
3D transistors coated on fin-structures and integrated circuits by a back-end-of-line (BEOL) compatible atomic layer deposition (ALD) process. High performance planar In
2
O
3
transistors with high mobility of 113 cm
²
/V • s and record high maximum drain current of 2.5 mA/μm are achieved by channel thickness engineering and post-deposition annealing. High-performance ALD In
2
O
3
based zero-V
GS
-load inverter is demonstrated with maximum voltage gain of 38 V/V and minimum supply voltage (V
DD
) down to 0.5 V. ALD In
2
O
3
3D Fin transistors are also demonstrated, benefiting from the conformal deposition capability of ALD. These results suggest ALD oxide semiconductors and devices have unique advantages and are promising toward BEOL-compatible monolithic 3D integration for 3D integrated circuits.