Write and read-out operations of novel 1T2C-type ferroelectric memory cells with an array structure

We fabricated a 1T2C-type ferroelectric memory array structure with 2 × 3 cells on a silicon-on-insulator (SOI) substrate. Each cell in the array is composed of a metal-oxide-semiconductor field-effect transistor (MOSFET) and two ferroelectric capacitors with the same area. This type of memory has unique features such as nonvolatile data storage, nondestructive data read-out, and high-density integration based on the scaling rule. It was found that binary data could be correctly stored into a selected cell of the memory array after optimizing the gate SiO₂ thickness of the MOSFET. It was also found that the written data could be correctly read out with a current ratio as large as 10 for "0" and "1" data.