Building a Silicon Quantum Computer Chip Atom by Atom

January 12, 2022

Jan. 12, 2022 — A University of Melbourne-led team has perfected a technique for embedding single atoms in a silicon wafer one-by-one. Their technology offers the potential to make quantum computers using the same methods that have given us cheap and reliable conventional devices containing billions of transistors.

A University of Melbourne led team have perfected a technique for embedding single atoms in a silicon wafer one-by-one. Credit: University of Melbourne

“We could ‘hear’ the electronic click as each atom dropped into one of 10,000 sites in our prototype device. Our vision is to use this technique to build a very, very large-scale quantum device,” says Professor David Jamieson of The University of Melbourne, lead author of the Advanced Materials paper describing the process.

His co-authors are from UNSW Sydney, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Leibniz Institute of Surface Engineering (IOM), and RMIT Microscopy and Microanalysis Facility.

“We believe we ultimately could make large-scale machines based on single atom quantum bits by using our method and taking advantage of the manufacturing techniques that the semiconductor industry has perfected,” he says.

Until now, implanting atoms in silicon has been a haphazard process, where a silicon chip gets showered with phosphorus which implant in a random pattern, like raindrops on a window.

“We embedded phosphorus ions, precisely counting each one, in a silicon substrate creating a qubit ‘chip,” which can then be used in lab experiments to test designs for large scale devices.”

“This will allow us to engineer the quantum logic operations between large arrays of individual atoms, retaining highly accurate operations across the whole processor,” says UNSW’s Scientia Professor Andrea Morello, a joint author of the paper. “Instead of implanting many atoms in random locations and selecting the ones that work best, they will now be placed in an orderly array, similar to the transistors in conventional semiconductors computer chips.”

“We used advanced technology developed for sensitive X-ray detectors and a special atomic force microscope originally developed for the Rosetta space mission along with a comprehensive computer model for the trajectory of ions implanted into silicon, developed in collaboration with our colleagues in Germany,” says Dr. Alexander (Melvin) Jakob, first author of the paper, also from the University of Melbourne.

This new technique can create large scale patterns of counted atoms that are controlled so their quantum states can be manipulated, coupled and read-out.

The technique developed by Professor Jamieson and his colleagues takes advantage of the precision of the atomic force microscope, which has a sharp cantilever that gently ‘touches’ the surface of a chip with a positioning accuracy of just half a nanometre, about the same as the spacing between atoms in a silicon crystal.

The team drilled a tiny hole in this cantilever, so that when it was showered with phosphorus atoms one would occasionally drop through the hole and embed in the silicon substrate.

The key, however, was knowing precisely when one atom—and no more than one—had become embedded in the substrate. Then the cantilever could move to the next precise position on the array.

The team discovered that the kinetic energy of the atom as it plows into the silicon crystal and dissipates its energy by friction can be exploited to make a tiny electronic ‘click.”

That is how they know an atom has embedded in the silicon and to move to the next precise position.

“One atom colliding with a piece of silicon makes a very faint click, but we have invented very sensitive electronics used to detect the click, it’s much amplified and gives a loud signal, a loud and reliable signal,” says Professor Jamieson.

“That allows us to be very confident of our method. We can say, “Oh, there was a click. An atom just arrived.” Now we can move the cantilever to the next spot and wait for the next atom.”

“With our Centre partners, we have already produced ground-breaking results on single atom qubits made with this technique, but the new discovery will accelerate our work on large-scale devices,” he says.

What is quantum computing and why is it important?

Quantum computers perform calculations by using the varied states of single atoms in the way that conventional computers use bits—the most basic unit of digital information.

But whereas a bit has only two possible values—1 or 0, true or false—a quantum bit, or qubit, can be placed in a superposition of 0 and 1. Pairs of qubits can be placed in even more peculiar superposition states, such as “01 plus 10,” called entangled states. Adding even more qubits creates an exponentially growing number of entangled states, which constitute a powerful computer code that does not exist in classical computers. This exponential density of information is what gives quantum processors their computational advantage.

This basic quantum mechanical oddness has great potential to create computers capable of solving certain computational problems that conventional computers would find impossible due to their complexity.

Practical applications include new ways of optimizing timetables and finances, unbreakable cryptography and computational drug design, maybe even the rapid development of new vaccines.

“If you wanted to calculate the structure of the caffeine molecule, a very important molecule for physics, you can’t do it with a classical computer because there are too many electrons,” says Professor Jamieson.

“All these electrons obey quantum physics and the Schrödinger equation. But if you’re going to calculate the structure of that molecule, there are so many electron-electron interactions, even the most powerful supercomputers in the world today can’t do it.

“A quantum computer could do that, but you need many qubits because you’ve got to correct random errors and run a very complicated computer code.”

Silicon chips containing arrays of single dopant atoms can be the material of choice for classical and quantum devices that exploit single donor spins. For example, group-V donors implanted in isotopically purified Si crystals are attractive for large-scale quantum computers. Useful attributes include long nuclear and electron spin lifetimes of P, hyperfine clock transitions in Bi or electrically controllable Sb nuclear spins.

Promising architectures require the ability to fabricate arrays of individual near-surface dopant atoms with high yield. Here, an on-chip detector electrode system with 70 eV root-mean-square noise (≈20 electrons) is employed to demonstrate near-room-temperature implantation of single 14 keV P+ ions.

The physics model for the ion–solid interaction shows an unprecedented upper-bound single-ion-detection confidence of 99.85 ± 0.02% for near-surface implants. As a result, the practical controlled silicon doping yield is limited by materials engineering factors including surface gate oxides in which detected ions may stop.

For a device with 6 nm gate oxide and 14 keV P+ implants, a yield limit of 98.1% is demonstrated. Thinner gate oxides allow this limit to converge to the upper-bound. Deterministic single-ion implantation can therefore be a viable materials engineering strategy for scalable dopant architectures in silicon devices.

More information: Alexander M. Jakob et al, Deterministic Shallow Dopant Implantation in Silicon with Detection Confidence Upper‐Bound to 99.85% by Ion–Solid Interactions, Advanced Materials (2021). DOI: 10.1002/adma.202103235

Journal information: Advanced Materials.


Source: Science in Public

Subscribe to HPCwire's Weekly Update!

Be the most informed person in the room! Stay ahead of the tech trends with industy updates delivered to you every week!

Meta’s Massive New AI Supercomputer Will Be ‘World’s Fastest’

January 24, 2022

Fresh off its rebrand last October, Meta (née Facebook) is putting muscle behind its vision of a metaversal future with a massive new AI supercomputer called the AI Research SuperCluster (RSC). Meta says that RSC will b Read more…

Supercomputer Analysis Shows the Atmospheric Reach of the Tonga Eruption

January 21, 2022

On Saturday, an enormous eruption on the volcanic islands of Hunga Tonga and Hunga Haʻapai shook the Pacific Ocean. The explosion, which could be heard six thousand miles away in Alaska, caused tsunamis across the entir Read more…

NSB Issues US State of Science and Engineering 2022 Report

January 20, 2022

This week the National Science Board released its biannual U.S. State of Science and Engineering 2022 report, as required by the NSF Act. Broadly, the report presents a near-term view of S&E based mostly on 2019 data. To a large extent, this year’s edition echoes trends from the last few reports. The U.S. is still a world leader in R&D spending and S&E education... Read more…

Researchers Achieve 99 Percent Quantum Accuracy with Silicon-Embedded Qubits 

January 20, 2022

Researchers in Australia and the U.S. have made exciting headway in the quantum computing arms race. A multi-institutional team including the University of New South Wales and Sandia National Laboratory announced that th Read more…

Trio of Supercomputers Powers Estimate of Carbon in Earth’s Outer Core

January 20, 2022

Carbon is one of the essential building blocks of life on Earth, and it—along with hydrogen, nitrogen and oxygen—is one of the key elements researchers look for when they search for habitable planets and work to unde Read more…

AWS Solution Channel

shutterstock 718231072

Accelerating drug discovery with Amazon EC2 Spot Instances

This post was contributed by Cristian Măgherușan-Stanciu, Sr. Specialist Solution Architect, EC2 Spot, with contributions from Cristian Kniep, Sr. Developer Advocate for HPC and AWS Batch at AWS, Carlos Manzanedo Rueda, Principal Solutions Architect, EC2 Spot at AWS, Ludvig Nordstrom, Principal Solutions Architect at AWS, Vytautas Gapsys, project group leader at the Max Planck Institute for Biophysical Chemistry, and Carsten Kutzner, staff scientist at the Max Planck Institute for Biophysical Chemistry. Read more…

Multiverse Targets ‘Quantum Computing for the Masses’

January 19, 2022

The race to deliver quantum computing solutions that shield users from the underlying complexity of quantum computing is heating up quickly. One example is Multiverse Computing, a European company, which today launched the second financial services product in its Singularity product group. The new offering, Fair Price, “delivers a higher accuracy in fair price calculations for financial... Read more…

Meta’s Massive New AI Supercomputer Will Be ‘World’s Fastest’

January 24, 2022

Fresh off its rebrand last October, Meta (née Facebook) is putting muscle behind its vision of a metaversal future with a massive new AI supercomputer called t Read more…

Supercomputer Analysis Shows the Atmospheric Reach of the Tonga Eruption

January 21, 2022

On Saturday, an enormous eruption on the volcanic islands of Hunga Tonga and Hunga Haʻapai shook the Pacific Ocean. The explosion, which could be heard six tho Read more…

NSB Issues US State of Science and Engineering 2022 Report

January 20, 2022

This week the National Science Board released its biannual U.S. State of Science and Engineering 2022 report, as required by the NSF Act. Broadly, the report presents a near-term view of S&E based mostly on 2019 data. To a large extent, this year’s edition echoes trends from the last few reports. The U.S. is still a world leader in R&D spending and S&E education... Read more…

Multiverse Targets ‘Quantum Computing for the Masses’

January 19, 2022

The race to deliver quantum computing solutions that shield users from the underlying complexity of quantum computing is heating up quickly. One example is Multiverse Computing, a European company, which today launched the second financial services product in its Singularity product group. The new offering, Fair Price, “delivers a higher accuracy in fair price calculations for financial... Read more…

Students at SC21: Out in Front, Alongside and Behind the Scenes

January 19, 2022

The Supercomputing Conference (SC) is one of the biggest international conferences dedicated to high-performance computing, networking, storage and analysis. SC Read more…

Q-Ctrl – Tackling Quantum Hardware’s Noise Problems with Software

January 13, 2022

Implementing effective error mitigation and correction is a critical next step in advancing quantum computing. While a lot of attention has been given to effort Read more…

Nvidia Defends Arm Acquisition Deal: a ‘Once-in-a-Generation Opportunity’

January 13, 2022

GPU-maker Nvidia is continuing to try to keep its proposed acquisition of British chip IP vendor Arm Ltd. alive, despite continuing concerns from several governments around the world. In its latest action, Nvidia filed a 29-page response to the U.K. government to point out a list of potential benefits of the proposed $40 billion deal. Read more…

Nvidia Buys HPC Cluster Management Company Bright Computing

January 10, 2022

Graphics chip powerhouse Nvidia today announced that it has acquired HPC cluster management company Bright Computing for an undisclosed sum. Unlike Nvidia’s bid to purchase semiconductor IP company Arm, which has been stymied by regulatory challenges, the Bright deal is a straightforward acquisition that aims to expand... Read more…

IonQ Is First Quantum Startup to Go Public; Will It be First to Deliver Profits?

November 3, 2021

On October 1 of this year, IonQ became the first pure-play quantum computing start-up to go public. At this writing, the stock (NYSE: IONQ) was around $15 and its market capitalization was roughly $2.89 billion. Co-founder and chief scientist Chris Monroe says it was fun to have a few of the company’s roughly 100 employees travel to New York to ring the opening bell of the New York Stock... Read more…

US Closes in on Exascale: Frontier Installation Is Underway

September 29, 2021

At the Advanced Scientific Computing Advisory Committee (ASCAC) meeting, held by Zoom this week (Sept. 29-30), it was revealed that the Frontier supercomputer is currently being installed at Oak Ridge National Laboratory in Oak Ridge, Tenn. The staff at the Oak Ridge Leadership... Read more…

AMD Launches Milan-X CPU with 3D V-Cache and Multichip Instinct MI200 GPU

November 8, 2021

At a virtual event this morning, AMD CEO Lisa Su unveiled the company’s latest and much-anticipated server products: the new Milan-X CPU, which leverages AMD’s new 3D V-Cache technology; and its new Instinct MI200 GPU, which provides up to 220 compute units across two Infinity Fabric-connected dies, delivering an astounding 47.9 peak double-precision teraflops. “We're in a high-performance computing megacycle, driven by the growing need to deploy additional compute performance... Read more…

Intel Reorgs HPC Group, Creates Two ‘Super Compute’ Groups

October 15, 2021

Following on changes made in June that moved Intel’s HPC unit out of the Data Platform Group and into the newly created Accelerated Computing Systems and Graphics (AXG) business unit, led by Raja Koduri, Intel is making further updates to the HPC group and announcing... Read more…

Nvidia Buys HPC Cluster Management Company Bright Computing

January 10, 2022

Graphics chip powerhouse Nvidia today announced that it has acquired HPC cluster management company Bright Computing for an undisclosed sum. Unlike Nvidia’s bid to purchase semiconductor IP company Arm, which has been stymied by regulatory challenges, the Bright deal is a straightforward acquisition that aims to expand... Read more…

D-Wave Embraces Gate-Based Quantum Computing; Charts Path Forward

October 21, 2021

Earlier this month D-Wave Systems, the quantum computing pioneer that has long championed quantum annealing-based quantum computing (and sometimes taken heat fo Read more…

Killer Instinct: AMD’s Multi-Chip MI200 GPU Readies for a Major Global Debut

October 21, 2021

AMD’s next-generation supercomputer GPU is on its way – and by all appearances, it’s about to make a name for itself. The AMD Radeon Instinct MI200 GPU (a successor to the MI100) will, over the next year, begin to power three massive systems on three continents: the United States’ exascale Frontier system; the European Union’s pre-exascale LUMI system; and Australia’s petascale Setonix system. Read more…

Three Chinese Exascale Systems Detailed at SC21: Two Operational and One Delayed

November 24, 2021

Details about two previously rumored Chinese exascale systems came to light during last week’s SC21 proceedings. Asked about these systems during the Top500 media briefing on Monday, Nov. 15, list author and co-founder Jack Dongarra indicated he was aware of some very impressive results, but withheld comment when asked directly if he had... Read more…

Leading Solution Providers

Contributors

Lessons from LLVM: An SC21 Fireside Chat with Chris Lattner

December 27, 2021

Today, the LLVM compiler infrastructure world is essentially inescapable in HPC. But back in the 2000 timeframe, LLVM (low level virtual machine) was just getting its start as a new way of thinking about how to overcome shortcomings in the Java Virtual Machine. At the time, Chris Lattner was a graduate student of... Read more…

2021 Gordon Bell Prize Goes to Exascale-Powered Quantum Supremacy Challenge

November 18, 2021

Today at the hybrid virtual/in-person SC21 conference, the organizers announced the winners of the 2021 ACM Gordon Bell Prize: a team of Chinese researchers leveraging the new exascale Sunway system to simulate quantum circuits. The Gordon Bell Prize, which comes with an award of $10,000 courtesy of HPC pioneer Gordon Bell, is awarded annually... Read more…

Nvidia Defends Arm Acquisition Deal: a ‘Once-in-a-Generation Opportunity’

January 13, 2022

GPU-maker Nvidia is continuing to try to keep its proposed acquisition of British chip IP vendor Arm Ltd. alive, despite continuing concerns from several governments around the world. In its latest action, Nvidia filed a 29-page response to the U.K. government to point out a list of potential benefits of the proposed $40 billion deal. Read more…

Julia Update: Adoption Keeps Climbing; Is It a Python Challenger?

January 13, 2021

The rapid adoption of Julia, the open source, high level programing language with roots at MIT, shows no sign of slowing according to data from Julialang.org. I Read more…

Top500: No Exascale, Fugaku Still Reigns, Polaris Debuts at #12

November 15, 2021

No exascale for you* -- at least, not within the High-Performance Linpack (HPL) territory of the latest Top500 list, issued today from the 33rd annual Supercomputing Conference (SC21), held in-person in St. Louis, Mo., and virtually, from Nov. 14–19. "We were hoping to have the first exascale system on this list but that didn’t happen," said Top500 co-author... Read more…

TACC Unveils Lonestar6 Supercomputer

November 1, 2021

The Texas Advanced Computing Center (TACC) is unveiling its latest supercomputer: Lonestar6, a three peak petaflops Dell system aimed at supporting researchers Read more…

10nm, 7nm, 5nm…. Should the Chip Nanometer Metric Be Replaced?

June 1, 2020

The biggest cool factor in server chips is the nanometer. AMD beating Intel to a CPU built on a 7nm process node* – with 5nm and 3nm on the way – has been i Read more…

Intel Launches 10nm ‘Ice Lake’ Datacenter CPU with Up to 40 Cores

April 6, 2021

The wait is over. Today Intel officially launched its 10nm datacenter CPU, the third-generation Intel Xeon Scalable processor, codenamed Ice Lake. With up to 40 Read more…

  • arrow
  • Click Here for More Headlines
  • arrow
HPCwire