Quinas Technology Ltd. (Lancaster, England) has been formed to develop a ‘universal’ non-volatile memory called UltraRAM, which has been in research for a number of years at the UK universities of Lancaster and Warwick.
The company is listed with two directors: business advisor and entrepreneur James Ashforth-Pook and Professor Manus Hayne of the Department of Physics at Lancaster, the inventor of the technology.
Ashforth-Pook told eeNews Europe the company was registered earlier this month and is currently participating in the Innovate UK iCURe program to continue developing the technology. Quinas was selected as a name to stand for QUantum Indium Arsenide, he added.
UltraRAM is based on quantum tunneling of electrons, triple-barrier resonant tunnelling (TBRT), within a layered compound semiconductor structure that can be manufactured on silicon wafers. (see UK team moves UltraRAM to silicon substrate). It has the ability to both store data for a long time – extrapolated to be more than 1,000 years – exceeding the capabilities in flash, but also to be read and written very quickly and at low energy similar to DRAM with an endurance of more than 10 million cycles. Hence being a dubbed a universal memory.
The universal memory has been an almost-abandoned ‘holy grail’ of solid-state memory research.
In addition, the company claims that UltraRAM is a highly efficient memory. The single-bit switching energy at a 20nm node would be about 100x below that of DRAM and 1,000x lower than flash and even more efficient than that when compared with other emerging non-volatile memories, the company states on its website.
Therefore UltraRAM holds out technical promise but does come at the expense of additional complexity in manufacturing.
The UltraRAM is similar to flash memory in that it stores data by moving electrons into or out of a floating gate. The charge state of the floating gate is read non-destructively by measuring the conductance of an underlying channel. The final component of the memory is the barrier that acts like a lock to retain electrons in the floating gate during data retention.
Normally the TBRT is highly resistive allowing data to be stored. However, when a voltage of approximately 2.5V is applied across the barrier electrons can flow via quantum resonant tunnelling. This takes place rapidly and allows the state of the memory to be changed rapidly and using little energy.
The active layers in the UltraRAM structure are made up of GaSb, InAs and AlSb deposited by molecular beam epitaxy. So far much of the manufacturing of test structures and devices has been done at the 20-micron and 10-micron geometry in the Lancaster University’s Quantum Technology Centre cleanroom