Emerging Non-Volatile Memory and Thin-Film Transistor Technologies for Future 3D-LSI

We present excellent performance of the two key devices in future 3D-LSI, HfO ₂ ferroelectric tunnel junction (FTJ) memory and poly-Si nanowire transistors. HfO ₂ FTJ has advantages such as CMOS compatibility, low operation current, self-compliance, and intrinsic diode properties. By scaling both ferroelectric layer and interfacial layer thickness, reduction of operation voltage while maintaining sufficient ON/OFF ratio was successfully demonstrated. High-mobility poly-Si nanowire transistors were realized by adopting advanced SPC (solid-phase crystallization) process. It was revealed that Coulomb scattering due to defects inside grains as well as defects at grain boundaries and enhanced surface roughness scattering are the major origins of mobility degradation in poly-Si transistors.