LAKE WALES, Fla. — As major electronics laboratories worldwide rush to invent a complementary metal oxide semiconductor (CMOS) quantum computer, Leti lays claim to the first quantum bit (qubit) fabricated on a standard 300-millimeter CMOS line. Leti (Laboratoire d'électronique, Grenoble), one three advanced-research institutes within CEA Tech (Centre d'études nucléaires des technologies), will present all the details at the International Electron Devices Meeting (IEDM 2016, Tuesday, Dec. 6) in a paper titled "SOI Technology for Quantum Information Processing."
Three-dimensional schematic of a silicon-on-insulator (SOI) nanowire field-effect transistor with two gates one for manipulation and the other for readout of a qubit.
"We have proved the concept of using a standard CMOS line to fabricate the quantum-dot qubits for a future quantum computer,” Maud Vinet, Leti’s advanced CMOS manager told EE Times in an exclusive interview.
The key to Leti's success is using super-cooled fully-depleted silicon on insulator (FD-SOI) to fabricate quantum-dots which can store and process spin-encoded qubits. The paper describing this accomplishment
titled A CMOS silicon spin qubit was written in cooperation with Inac (the Institute de Nanosciences et Cryogenie, France) and the University of Grenoble Alpes.
Qubit device top view obtained by scanning electron microscopy after the fabrication of gates and spacers.
In more detail, the qubit was fabbed using p-type transistors in a twin-gate configuration with transistors using undoped channels. When cooled to low temperatures (but not using superconductivity) the first gate acts as a quantum dot encoding the charge carrier's (hole's) spin — the qubit. Its quantum state is defined by phase-tunable microwave modulation.The second in-line gate acts as an easy way to read-out the first qubit. Leti claims that by encoding the spin on a hole charge carrier in a p-type material (instead of on an electron in a n-type material) enables the reduction of the readout circuitry to a single gate.
Superconducting gates are already being used to encode qubits at D-Wave and elsewhere, but Leti claims its does not use superconductivity, despite the 10 milli-Kelvin temperature, but rather standard quantum dots to encode qubits. As a result it claims to opens the door to leveraging standard CMOS processing to create a new "More than Moore" era of quantum computing.
Transmission-electron-microscopy (TEM) image of the dual-gate qubit device along a longitudinal cross-sectional plane.
The European Union is already developing a supercooled infrastructure to commercialize future CMOS quantum computers that integrate both quantum and conventional digital computers. Its applications areas include parallel processing, quantum cryptography, database searching and simulation of physical quantum processes for other areas of science.
— R. Colin Johnson, Advanced Technology Editor, EE Times
Article corrected 12/7/2016, 8:58 AM PT: We mistakenly identified Inac as the Instituto Nacional de Aeronáutica Civil, Venezuela. Inac is the Institute de Nanosciences et Cryogenie, France.