Rambus buys Unity Semiconductor

Rambus has purchased Unity Semiconductor for the tidy sum of $35 million, less than half of the company’s initial $75 million VC investment.

Unity Semiconductor owns several memory patents, 147 to be precise, and in particular those relating to a non-volatile Flash memory technology that goes by the name of CMOx (Conductive Metal Oxide).

CMOx works by moving oxygen ions between conductive and insulating metal-oxide layers within a single chip. It has been developed by Unity, uses IBM’s cross-bar memory technology, and is an alternative to NAND Flash. It promises to eradicate the ubiquitous NAND Flash used in so many of our favourite gadgets.

CMOx offers higher storage density, due to its three-dimensional structure, and simpler manufacturing design than NAND. It features a much smaller cell size than NAND (resulting in more cells per wafer) and lower power requirements. As things stand, CMOx is cheaper to manufacture than NAND, promises up to ten times faster writes and will have four times the storage capacity at 17nm. The greatest advantage of CMOx, however, seems to be that it doesn’t rely on untested technology. It can be manufactured with today’s CMOS manufacturing tools, only not as dense as its projected 17nm capacity of 1Tb.

The technology itself, however, is already going on nine years old, which begs several questions. If it is so good, why does NAND even register? Our best explanation is that the now-defunct Unity Semiconductor was not a sales-, but a chip design company, inexperienced in the ways of licensing, which it even tried last year.

At the beginning of 2011, Unity Semiconductor signed an agreement with Micron, with the prospect of commercialising CMOx products, but it now seems nothing good came of it, playing the company right into Rambus’ expert IP-licensing hands. It is now up to Rambus to license off the IP to the likes of Samsung, Toshiba, Hynix Micron and, who knows, maybe Intel.