Resistive RAM startup Crossbar Inc. (Santa Clara, Calif.) has raised $25 million in an oversubscribed Series C funding round bringing the amount raised by the company to $50 million.
Crossbar plans to use the funds to complete manufacturing and licensing operations and said it is now finalizing agreements with multiple semiconductor companies and plans to announce its first licensing agreements with several customers later in 2014.
Existing investors Artiman Ventures, Kleiner Perkins Caufield & Byers, Northern Light Venture Capital and the University of Michigan participated and were joined by new investors included SAIF Partners, Korea Investment Partners, CBC-Capital and Tao Invest.
The company has demonstrated a 1-Mbyte storage device for embedded code and said that this shows that Crossbar's technology is ready for production with "promising yields and performance measures."
Crossbar was formed in 2010 to commercialize a body of non-volatile memory device research based on metal-ion migration and filament formation within amorphous silicon that was being led by Professor Wei Lu at the University of Michigan. Professor Lu serves as the company's chief scientific officer. The company has selected silver as the material to form conductive filaments and is touting the technology as the basis of both multi-layered terabyte stand-alone memory ICs as a non-volatile memory embedded within logic SoCs.
Crossbar's memory is based on a silver top electrode and polysilicon bottom electrode with insulating amorphous silicon in the middle. A writing voltage causes silver ions to migrate through the silicon to form a filament that eventually connects top and bottom electrodes. A reverse voltage causes the silver ions to move and break the filament. Lower voltages can be used to "read" the connection as a 1 or 0.
However, there has been some uncertainty around the basic operation of the several variants of resistive RAM and memristor that have been researched over the last decade. There are concerns that those that are based on the making and breaking of filaments may lack reliability or be sensitive to the temperature.
Crossbar's technology shows similarities to that of Adesto Technologies Inc. (Sunnyvale, Calif.) Adesto's technology is based on programmable metallization cell (PMC) technology licensed from Axon Technologies Corp., a spin-off of Arizona State University. Adesto's development work is based on copper as the migrating ion in its conductive–bridging RAM (CBRAM).
"The response to Crossbar’s RRAM technology has been truly overwhelming and we are now actively engaged in discussions with some of the leaders in the electronics and semiconductor markets," said George Minassian, CEO of Crossbar, in a statement. "Our Crossbar team consists of some of the best and brightest minds in the memory industry and our investors are among the most respected. With this latest round of funding we can further accelerate our market momentum, and more rapidly bring our technology to market."
At the time of Crossbar's emergence in August 2013 Minassian said he expected the company's technology to be commercially available as embedded memory in 2015 and as a stand-alone memory two or three years after that.
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