What Is Ferroelectric Random Access Memory (FRAM)?
Ferroelectric random access memory (FRAM) is a non-volatile semiconductor memory that utilizes the polarization properties of ferroelectric capacitors to store data. Unlike volatile SRAM and DRAM, FRAM retains data when power is off, combining the advantages of high-speed operation, low power consumption, and endurance to frequent rewrites.
Applications of FRAM
FRAM’s unique attributes make it ideal for various applications, including IC cards, RF tags, smart meters, drive recorders, medical monitors, POS systems, counters, and industrial robots. Its integration into microcontrollers promises enhanced performance and efficiency over traditional memory solutions.
Principle of FRAM
FRAM operates on the principle of altering the polarization direction within a ferroelectric capacitor to represent data. This process involves a multi-step sequence of applying voltage to write and read data, supported by a layered cell structure for efficient operation.
Writing and Reading Data
Data writing in FRAM is achieved by polarizing the ferroelectric capacitor through applied voltage, with the direction of residual polarization indicating the stored data. Reading data involves sensing the charge transfer caused by polarization reversal, necessitating a subsequent rewrite to maintain data integrity.
Structure of FRAM
The fundamental FRAM cell, known as the 1T1C type, mirrors the DRAM configuration but employs ferroelectric capacitors for data storage. This structure necessitates additional components like plate lines for proper operation and data retention.
Considerations in FRAM Technology
- Plate Lines: Essential for reading data, plate lines activate the ferroelectric capacitor to facilitate polarization readout.
- FET-Type FRAM: An alternative design using ferroelectric materials in the FET gate insulating film, aiming to reduce cell area but with shorter data retention times.
- Remnant Polarization: The basis for data storage in FRAM, relying on the persistent polarization of ferroelectric materials even after the electric field is removed.
FRAM’s technological advancements, including its non-volatile nature, energy efficiency, and rapid operation, position it as a promising alternative in the memory landscape, especially for applications demanding durability and frequent data updates.