Hitachi and Renesas Technology Develop Low-Power MOS Phase-Change Memory Cells for On-Chip Memory of Microcontrollers
TOKYO—(BUSINESS WIRE)—Dec. 13, 2005—
Renesas Technology Corp.:
-- The new cell, which can be programmed at a 1.5V power supply
voltage with only a 100uA programming current, is a promising
solution for the on-chip nonvolatile memory of next-generation
microcontrollers for embedded systems.
Hitachi, Ltd. (NYSE:HIT)(TOKYO:6501) and Renesas Technology Corp.
today announced the successful prototyping of low-power phase-change
memory cells. The nonvolatile semiconductor storage elements can be
programmed at a power supply voltage of 1.5V and a low current of
100uA -- about 50 percent less power consumption per cell than
previous technology reported by Hitachi and Renesas. Moreover, the new
phase-change cells compare favorably with existing nonvolatile memory
in terms of high-speed writing and reading capabilities, high
programming endurance, small size, and high-level integration. Thus,
they provide a promising solution for on-chip program and data storage
in next-generation microcontrollers for embedded applications such as
information devices, home electric appliances, and in-vehicle
equipment and control systems.
The prototype cells were fabricated in a 130-nanometer CMOS
process. Their structure uses MOS transistors and a phase-change film
that enters an amorphous state(1) (high resistance) or crystalline
state (low resistance) in response to heat. They are programmed to one
state or the other via a tungsten bottom-electrode contact (BEC) with
a diameter of 180nm. In a read operation, the stored digital (1 or 0)
information is determined from a difference in the amount of current
flowing in the film.
To obtain the breakthrough power-consumption results, the Hitachi
and Renesas researchers developed an original phase-change film with
low-current, low-voltage programming capability. They produced the
film by controlled oxygen doping of a germanium-antimony-tellurium
(GeSbTe) material. The oxygen doping enables the resistance of the
phase-change film to be constrained to an optimal level and suppresses
the flow of excessively large currents during programming. Also, the
cell implementation allows the gate widths of the MOS transistors
forming the cells to be decreased and the drive output MOS transistors
to be reduced, making it possible to shrink the size of the memory
cells and drive circuitry.
Details of the breakthrough low-power MOS phase-change memory cell
technology were revealed in a technical paper presented at the
International Electron Devices Meeting held in Washington D.C. from
December 5, 2005.
About Hitachi, Ltd.
Hitachi, Ltd., (NYSE:HIT), headquartered in Tokyo, Japan, is a
leading global electronics company with approximately 347,000
employees worldwide. Fiscal 2004 (ended March 31, 2005) consolidated
sales totaled 9,027.0 billion yen ($84.4 billion). The company offers
a wide range of systems, products and services in market sectors
including information systems, electronic devices, power and
industrial systems, consumer products, materials and financial
services. For more information on Hitachi, please visit the company's
Website at http://www.hitachi.com.
About Renesas Technology Corp.
Renesas Technology Corp. designs and manufactures highly
integrated semiconductor system solutions for automotive, mobile and
PC/AV markets. Established on April 1, 2003 as a joint venture between
Hitachi, Ltd. (TOKYO:6501)(NYSE:HIT) and Mitsubishi Electric
Corporation (TOKYO:6503) and headquartered in Tokyo, Japan, Renesas
Technology is one of the largest semiconductor companies in the world
and the world-leading microcontroller supplier globally. Besides
microcontrollers, Renesas Technology offers system-on-chip devices,
Smart Card ICs, mixed-signal products, flash memories, SRAMs and more.
www.renesas.com
(1) Amorphous state: A state in which the atoms or molecules
making up a solid do not have a regular structure, such as a
crystalline structure. (Also referred to as a noncrystalline state.)
Contact:
Renesas Technology Corp.
Yoshinobu Sato, +81 (3) 6250-5554 (Japan)
Email Contact
or
Renesas Technology America Inc.
Akiko Ishiyama, 408-382-7407 (U.S.)
Email Contact
or
Renesas Technology Europe Ltd.
Jonathan Colbourne, +44-1628-585163 (Europe)
Email Contact
or
Hitachi, Ltd.
Hiroki Inoue, +81 (3) 5208-9323 (Japan)
Email Contact
or
Hitachi America, Ltd.
Matt Takahashi, 650-244-7902 (U.S.)
Email Contact
or
Hitachi Europe Ltd.
Masanao Sato, +44-1628-585379 (Europe)
Email Contact
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