Embedded ferroelectric memory technology with completely encapsulated hydrogen barrier structure

A 0.18-μm system LSI embedded ferroelectric memory (FeRAM) operating at a very low voltage has been developed for the first time. The low-voltage operation has been attained by newly developed stacked ferroelectric capacitors completely encapsulated by hydrogen barriers, which enable us to eliminate hydrogen reduction of the ferroelectric thin film during the back end of the line process including FSG, tungsten CVD (W-CVD), and plasma CVD SiN (p-SiN) passivation. A fabricated 1-Mbit one-transistor one-capacitor SrBi₂(Ta_xNb_1-x)₂O₉ (SBTN)-based embedded FeRAM operates at a low voltage of 1.1 V and ensures the endurance cycles up to 10¹² at 85°C and the data retention time up to 1000 h at 125°C, which is the most promising for mass production of 0.18-μm low-power system LSI-embedded FeRAM and beyond.