High-κ Insulator Thin Films and Retention Properties of MFIS Diodes

Abstract

ABSTRACTFerroelectric field effect transistor (FFET) is a promising candidate for non-volatile random access memory because of its high speed, single device structure, low power consumption, and nondestructive read-out operation. Currently, however, such ideal devices are commercially not available due to poor interface properties between ferroelectric film and Si substrate, such as leakage current and interdiffusion etc. So we choose YSZ and HfO2 insulating thin films as buffer layer due to they possess relatively high dielectric constant, high thermal stability, low leakage current, and good interface property with Si substrates. Two structural diodes of Pt/BNT/YSZ/Si and Pt/SBT/HfO2/Si were fabricated, and the microstructures, interface properties, C-V, I-V, and retention properties were investigated in detail. Experimental results show that the fabricated diodes exhibit excellent long-term retention properties, which is due to the good interface and the low leakage density, demonstrating that the YSZ and HfO2 buffer layers are playing a critical modulation role between the ferroelectric thin film and Si substrate.