Interlayer-Free Ferroelectric Transistors via Depletion Charge Boosting in Oxide Channel for Neuromorphic Applications

초록

Oxide semiconductors are considered one of the promising candidates to replace silicon as the channel material in ferroelectric field-effect transistors (FeFETs), owing to their compatibility with low-temperature complementary metal-oxide-semiconductor (CMOS) processing. However, intrinsic hole deficiency in oxide semiconductors limits complete ferroelectric polarization switching, and practical channel engineering strategies to overcome this limitation have rarely been demonstrated. This study demonstrates a depletion charge boosting method via in situ Ar+ plasma treatment during atomic layer deposition of the indium-gallium oxide (IGO) channel. Under the optimized plasma treatment condition (300 W for 60 s), plasma-induced ionized oxygen vacancies in the IGO front channel function as depletion charges that compensate for the negative bound charges in the zirconium-doped HfO2 (HZO) layer. The engineered IGO/HZO FeFETs exhibit an improved memory window of 1.612 V, potentiation/depression cycling up to 5120 pulses, and stable multi-level retention of 100 s for 64 conductance states. Furthermore, the multilayer perception-based artificial neural network simulations yield a recognition accuracy of approximately 89% after 125 training epochs. This depletion charge boosting technology provides a potential pathway for improving oxide channel-based FeFETs toward neuromorphic applications.