ULTRARAMTM is a revolutionary new type ofcomputer memory that was invented in thePhysics Department at Lancaster University
and is being commercialised by Quinas
Technology Ltd.

It combines speed, endurance, retention
and energy efficiency into a single memory
concept. These astonishing properties
are achieved by harnessing a quantum
mechanical effect called resonant tunnelling.

Just two complimentary types ofmemory, DRAM and flash, represent
more than 95% of the >$100bn peryear memory market.

DRAM

Endurance
Speed

Non-volatileNon-destructive
readENERGY EFFICIENCYDRAM and flash are ubiquitous in digital electronics
and computing from internet of things (IoT) devices,
through to consumer electronics and appliances,smartphones, personal computers and data centres.
The inherent properties of DRAM (dynamic random
access memory) and flash allows them to excel in
specific roles, but makes them unsuitable for others.
DRAM is fast and can be rewritten almost endlessly(high endurance) so is used as active or working
memory, whereas flash is slow and cheap and usedfor storage.
The conventional view is that these complementaryroles are unavoidable, since data that is stored very
robustly (non-volatile, like flash) must be difficult
to change, while data in a fast memory (like DRAM)
that is easily changed has to be somewhat fragile(volatile).

FLASH

ULTRARAMTM combines the advantageous
properties of these two memory types into asingle, energy-efficient package, without any of thedrawbacks. A major benefit of replacing existing
memories with ULTRARAMTM is the reduction inenergy consumption. Data centres already consume
more electricity then Belgium and The Netherlands
combined, and this is only expected to increase,potentially reaching 20% of global electricity by2030.
A significant amount of this energy is consumed bymemories – either in retaining data in active memory,or moving it between active memory and storage.
ULTRARAMTM’s combination of non-volatility, speed
and high efficiency could greatly reduce IT energy
consumption, helping to achieve net-zero carbonemissions.

How does it work?

ULTRARAMTM is a charge-based memory that stores data by moving electrons into or out of a socalled ‘floating gate’. The charge state of the floating gate is read non-destructively by measuring theconductance 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. The barrier is unlocked to allow
charge to flow when the memory is being written or erased. In ULTRARAMTM, a triple-barrier resonanttunneling (TBRT) structure is the revolutionary component that give it its remarkable properties.
Normally, the TBRT is highly resistive (locked), allowing data to be stored in the memory for over 1,000years. However, when a small voltage of just ~2.5 V is applied to the device, the barrier is unlocked andelectrons can rapidly pass through it. This process occurs by a quantum mechanical phenomenon
called resonant tunnelling, and it allows the logic state of the memory to be switched extremely
quickly and with very little energy.
The active layers in ULTRARAMTM are made up of compound semiconductors GaSb,
InAs and AlSb deposited by a technique called molecular beam epitaxy; in the TBRT they
are just a few atomic layers thick! Devices (chips) are then fabricated in Lancaster
University’s Quantum Technology Centre cleanroom.

Transmission electron microscopy images courtesy of University or Warwick.

Website: quinas.tech
Contact us for further information: info@quinas.tech
Engineering andPhysical Sciences
Research Council

Innovate
UK

This work was and is supported by the EPSRC, UK, via the Innovate UK ICURe Explore and Exploit research accelerator programs, the 2017-2020
IAA funding allocation to Lancaster University under grant EP/R511560/1, a scholarship under grant EP/N509504/1, equipment funding under grant
EP/T023260/1 and the Future Compound Semiconductor Manufacturing Hub grant EP/P006973/1, and by the European Commission via ATTRACT
projects funded under grant agreements 777222 and 101004462 and MSCA-ITN QUANTIMONY under grant agreement 956548.