Enhanced electrical performances with HZO/β-Ga2O3 3D FinFET toward highly perceptual synaptic device application

초록

In this study, we have demonstrated a novel high-performance ferroelectric FinFET (Fe-FinFET) that integrates ultra-wide-bandgap (UWBG) beta-gallium oxide (/3-Ga2O3) channel with an atomic layer deposited (ALD) hafnium zirconium oxide (HZO) ferroelectric layer for the first time, and experimentally validated the effectiveness of the robust /3-Ga2O3 platform as a memory application. Compared with conventional planar ferroelectric FET (FeFET), the Fe-FinFET exhibits a markedly wider counter-clockwise hysteresis loop in its transfer characteristics, achieving a large memory window (MW) of 13.9 V with a single HZO layer. When normalized to the actual channel width, the Fe-FinFETs show an improved ION/IOFF ratio of 2.3 x 107 and a subthreshold swing value of 110 mV/dec; Y-function method further indicates that the intrinsic mobility is improved to 4.25 x 102 cm2/Vs. The enhanced polarization due to larger electric fields across the ferroelectric layer in Fe-FinFET is validated using Sentaurus TCAD, and this result is further supported by the energy-dependent distribution of interface trap density (Dit) extracted in both forward and reverse sweep directions. After 5 x 106 program/erase (PGM/ERS) cycles, the MW was maintained at 9.2 V, and the retention time was measured up to 3 x 104 s with low degradation. To verify its potential as an artificial synapse, we trained a convolutional neural network (CNN) and achieved an accuracy of 91.7 %. These results establish the HZO//3-Ga2O3 Fe-FinFET as a promising candidate for high voltage-enduring, non-volatile memory devices that also offer synaptic functionality for neuromorphic applications.

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