Texas Instruments and Ramtron advance FRAM technology to 130 nanometer process

“This manufacturing agreement marks a major leap forward in the commercialisation of higher-density FRAM products,” said Ramtron CEO Bill Staunton. “Ramtron will capitalise on TI’s proven, advanced 130nm process technology and advanced manufacturing capabilities with high-density stand-alone FRAM memories. In addition to a 4-Mb device, we are planning to sample at least one additional product off of the TI line in 2007.”

“Our joint collaboration with Ramtron and commercialisation of FRAM technology on TI’s 130nm process sets a new standard for the production of high density FRAM devices,” said Dr. Ted Moise, director of FRAM development at TI. “Through straightforward additions to our standard 130nm manufacturing process, we have achieved cost, power and performance standards that will be difficult for other embedded non-volatile memory technologies to match.”

To create the embedded FRAM module, TI added only two additional mask steps to its standard, 130nm copper-interconnect process. By moving to a 130nm process, the companies will deliver Ramtron’s 4-Mb FRAM memories using the smallest commercial FRAM cells shown-to-date, measuring only 0.71µm², and enabling a higher memory density than that achieved with SRAM cells. To achieve this cell size, the process features an innovative capacitor-over-plug process that places the non-volatile capacitor stack directly on top of the W-plug transistor contact.

FRAM memory combines the fast access and low-power qualities of volatile DRAM with the ability to retain data without power. Other non-volatile memories such as EEPROM and Flash are less efficient to embed because of multiple mask steps, longer write times, and increased power required to write data. In addition, FRAM’s small cell size and minimal mask additions allow FRAM to be produced at a lower cost than SRAM for embedded applications. FRAM also consumes much lower power than MRAM and is already commercially proven in demanding automotive, metering, industrial and computing applications.

“FRAM’s fast access time, low power dissipation, small cell size, and affordable manufacturing cost means it is well suited for a wide range of applications,” continued Dr. Moise. “Systems requiring low-power, non-volatile memory, fast data protection prior to power-down, or unlimited write endurance will benefit greatly from FRAM’s capabilities.”

At the core of FRAM technology are tiny ferroelectric crystals integrated into a capacitor that allow FRAM products to operate like fast non-volatile RAMs. The electric polarisation of the ferroelectric crystals is shifted between two stable states by the application of an electric field. The direction of this electric polarisation is sensed by internal circuits as either a high or a low logic state. Each orientation is stable and remains in place even after the electric field is removed, preserving the data within the memory without periodic refresh.

TI fabricates planar FRAM cells using a capacitor-on-plug approach to minimise cell area. The ferroelectric capacitor is formed using Iridium electrodes and a thin Lead Zirconate Titanate (PZT) ferroelectric layer.