Z-RAM to Take on DRAM with Hynix Deal
By Samuel K. Moore
First Published August 2007
Swiss company's technology could double the density of
memory chips
13 August 2007—The Swiss memory company Innovative
Silicon says it has struck a deal to license its
technology to the No. 2 maker of standalone DRAM memory
chips, Hynix Semiconductor, based in Inchon, South
Korea. The technology, called Z-RAM (for zero-capacitor
DRAM), could potentially double the density of Hynix’s
memory chips. Until now, Innovative Silicon’s technology
had been considered only for use as memory embedded on
microprocessors and other logic chips, where it would
replace or augment caches of SRAM. The deal moves
Innovative Silicon, based in Lausanne, Switzerland, into
a new market worth more than US $30 billion, making the
total market it could serve more than $100 billion.
During an
interview with IEEE Spectrum last year,
Innovative Silicon’s CEO, Mark-Eric Jones hinted that a
DRAM license was in the works.
Sung-Joo Hong, vice president of R&D at Hynix
calls Z-RAM “an elegant approach to manufacture dense
DRAMs.” The technology could help Hynix create a whole
new platform of products, he adds.
Terms of the deal were not disclosed. Innovative
Silicon would say only that the license and engineering
fee would be worth “eight figures” and that if Hynix
puts the technology into production there would be
royalties at that time. It is the Swiss firm’s second
license. The first went to the U.S. microprocessor firm
Advanced Micro Devices (AMD) in late 2005.
Z-RAM replaces the six transistors of SRAM and the
transistor-plus-capacitor structure of DRAM with a
single transistor. While the semiconductor industry has
been able to steadily shrink the size of transistors for
some 40 years, DRAM makers have the added difficulty of
shrinking capacitors, which are used to store bits.
Capacitors cannot shrink at the same rate, because they
must be able to store a recognizable amount of charge.
The capacitor in a DRAM cell is therefore much larger
and more difficult to construct than the transistor.
In a Z-RAM cell, the bit is stored as charge within
the transistor itself, doing away with the capacitor.
However, Z-RAM works only if the chip is built from a
silicon-on-insulator (SOI) wafer. Such wafers contain a
layer of silicon dioxide insulation buried below a
silicon surface. Certain microprocessor makers, notably
Sunnyvale, Calif.–based AMD, make their chips on SOI
wafers to reduce the amount of power they draw and
improve performance. At the moment, none of the major
DRAM makers, Hynix included, uses SOI.
Before developing Z-RAM at Ecole Polytechique
Fédérale de Lausanne, Innovative Silicon cofounder
Pierre Fazan, was an engineer at one of Hynix’s
competitors, Micron Technology Inc., in Boise, Idaho.
Also on Spectrum Online
“Masters
of Memory,” January 2007
“Price
Fixing in the Memory Market,” December 2004
“Embedded
DRAM Chips on the Rise,” March 2007