George Nakane

A 256 kb nonvolatile ferroelectric memory at 3 V and 100 ns

One of the most important features for ferroelectric material is fast write at low voltage. This feature is used in a 256 kb nonvolatile memory that operates at 3 V power supply with a read/write time of 100 ns. Active current is 3 mA at 200 ns cycle time at 3 V for battery operation. The cell consists of 1 transistor and 1 capacitor per bit (1T1C) permitting a high level of integration. For low-voltage low-power operation, use is made of a preset reference-cell circuit, wordline boost circuits with a ferroelectric boosting capacitor and a divided-cell plate circuit.<<ETX>>

2 V/100 ns 1 T/1 C nonvolatile ferroelectric memory architecture with bitline-driven read scheme and non-relaxation reference cell

Recently, a nonvolatile memory embedded in microcontrollers has been required to have 100 ns access time at 2.0 V for mobile information terminals operating with a re-chargeable battery. To achieve this, this paper proposes new architecture for a ferroelectric nonvolatile memory (FeRAM) comprised of (a) Bitline-Driven Read Scheme and (b) Non-Relaxation Reference Cell for high speed and low voltage operation respectively. Using this architecture, a FeRAM with one transistor and one capacitor per bit (1T/1C) cell can have a performance of 100 ns access time at 2.0 V.