According to the Wall Street Journal, a new memory
technology, to be commercialised within two years, will take over
from NAND flash which is seen to have scaling difficulties after
the 32nm generation.
After working in stealth mode for seven years,
Unity Semiconductor
is reported to be on the verge of taping out a 64Gbit memory which
will scale to 20nm.
"We see ourselves in the two year horizon for production volumes
of our first product, a 64 Gigabit storage class memory," said
Unity Semiconductor chairman, president & CEO, Darrell
Rinerson, a former executive at Micron.
Unity, founded in 2002, says it has created the world's first
passive rewritable crosspoint memory array that requires no
transistors in a memory cell. Unity Semiconductor has been
processing 64K products for 2 years, 64Mbit products for 1 year,
and is in design of a 64Gbit product that is now close to tape-out
and slated for pilot production in 2H 2010, with volume production
in 2Q 2011.
Unity has closed its Series C round of financing of $22m. The
financing came primarily from August Capital, Lightspeed Venture
Partners, and Morgenthaler Ventures and a major hard disk drive
(HDD) manufacturer, also a repeat investor. The latest round brings
total funding to nearly $75m.
The company's says it has produced 'the world's first R/W
passive cross-point memory array. There is no transistor in memory
cell. It is a non-volatile, multi-layer, multi-cell memory with
0.5F2 memory cell size and a fast write spead. The write speed is
said to be between five and ten times faster than NAND.
'CMOx is a next-generation NVM technology based upon a
Unity-proprietary switching effect that occurs in certain metal
oxide combinations', says the web-site, 'the switching concept is
different from that used in today's flash technology. The memory
effect of CMOx technology is based upon the movement of ionic
charge carriers. CMOx can be utilized to form a passive cross-point
multi-layer memory array, as it does not require a transistor per
cell. Other memory technologies, such as phase-change memory (PCM)
and magneto-resistive random access memory (MRAM), use a transistor
per cell and are not amenable to the cross-point multi-layer chip
architecture.
The site adds: 'The multi-layer cross-point array utilizes a
resistance change element (although it's not a Resistive RAM (RRAM)
memory cell such as is being developed by a few other companies).
Rather, in the CMOx technology, conduction is uniform across the
device instead of being filamentary. The cross-point memory array
architecture allows for the densest memory devices of all the
next-generation NVM technologies. Further, it enables the physical
stacking of multiple layers of memory. Unity Semiconductor's CMOx
based designs use 4 physical layers of multi-level cell (MLC)
memory, and is the key to increasing the density of its
storage-class memory products. A proprietary next-generation
nonvolatile memory technology, CMOx will yield products with 4x the
density and 5-10x the write speed of today's NAND flash.'
As well as manufacturing its own discrete memory products based
on CMOx, the technology will be available for 'selective IP
licensing' says Unity.
"The technology can be scaled below 20nm, says Unity, with a
volumetric density better than 4bits/cell NAND. It uses less than 1
microamp of write
current per cell, has a 10x write performance and better
endurance compared to NAND, and at a much lower cost," stated Alan
Niebel, CEO of WebFeet Research.
Unity is looking at innovative business models. 'Key among
these', states Unity, 'is the separation of the processing of the
front-end-of-line (FEOL) CMOS base wafer from the Back-end-of-line
(BEOL) memory layer processing'.
'No new process technology is needed in the CMOS base wafer,
which can be fabricated at a CMOS logic foundry with existing
production capability and capacity on a trailing edge CMOS (90 nm)
process'.
'The BEOL memory concept enables a CMOS logic foundry to be in
the memory business without taking significant risks associated
with being in the memory business'.
'Unity Semiconductor's CMOS FEOL strategy allows it to be a
moderate follower in CMOS transistor technology. Its shrink path is
unconventional in that a higher density memory core doesn't require
base CMOS technology migration. Instead, Unity can use the same
90nm base CMOS for multiple generations, as well as use proven
design IP to reduce risk and time to market.'
Unity's BEOL Memory manufacturing strategy calls for it to form
a joint venture partnership(s) for volume production with a
top-tier IDM already in the memory business. This joint-venture
BEOL Memory manufacturing facility will procure the CMOS base
wafers from existing CMOS logic foundries. The CMOx memory layers
will then be deposited on the CMOS base wafers in the joint venture
BEOL memory fab.
Unity's CMOx memory technology, in a multi-layer
cross-point array architecture using MLC, achieves an industry
leading cell size of 0.5F2.
View a quick demo of how the technology
works.
See also: Mannerisms, the blog of David
Manners. Updated twice daily, it's the distinctive, entertaining,
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