A quantum leap in semiconductor technology

Quantum technology is promising to make fundamental changes to how we process and transfer ­information. Quantum processors are ­already available on the market. At the same time, ­researchers are working on combining conventional semiconductor technology and quantum systems – and thereby creating a completely new form of semiconductor electronics. 

The year 2022 marks a milestone in the history of digitalisation: for the first time, almost two thirds of global GDP is being generated digitally, as forecast by an IDC study. The fundamental basis for this are reliable, high-performance IT systems and infrastructures. Quantum computers are extremely powerful and are therefore perfectly suited to processing the growing data volumes from the economy and society. 

Many times the performance

Quantum computers are intended to outperform conventional computers many times over because they work completely differently. Instead of classic bits, which can assume the value of 0 or 1, they use so-called quantum bits, which can be 0 and 1 at the same time. “This gives them enormous potential for tackling problems which classic computers cannot solve. In particular, they are promising to be able to solve important problems in the fields of logistics and medicine development. They are a central, key technology of the 21st century,” says Prof Klaus Sengstock, Head of Group at the Institute of Laser Physics at Universität Hamburg – in the next five years, a functioning quantum optimiser is to be created as part of a research project at the university. There are different options for constructing qubits. Photons, ions or superconducting circuits can form the physical basis for such designs. 

The global competition for the most powerful quantum computer has long been in full swing, with the markets of the future at stake. Subsidies, research groups and leading companies are shaping the dawn of the quantum age. “In quantum computing, we have reached a degree of maturity where this technology no longer just belongs in the lab,” explains Dr Walter Riess, Head of the Science & Technology department at IBM Research in Zurich, which has been awarded two Nobel prizes. 

Quantum processors are becoming more suited to application

The first quantum processors are already on the market: in 2021 IBM presented a quantum processor with 127 qubits. The group is aiming to build a quantum processor with over 1,000 qubits by 2023. A processor from QuEra Computing has 256 qubits and it should soon be available to customers. QuEra is using research results about neutral atoms, developed at Harvard University and the Massachusetts Institute of Technology, as the basis of its scalable, programmable quantum computer solution. The hardware uses arrays of neutral atoms in which hundreds of atoms are cooled and then arranged in small vacuum chambers by laser fields. While the glass walls of the chambers are at room temperature, just millimetres away, the atoms are laser-cooled to one millionth of a degree Kelvin above absolute zero. That is more than a million times colder than space and over a thousand times colder than the superconducting qubits from other industry figures such as IBM and Google. “There is an enormous opportunity to make headway on some of today’s most critical – and presently impossible – problems that impact nearly every one of us,” said Alex Keesling, CEO of QuEra and co-inventor of QuEra’s technology. “With our first machine, we are excited to begin to demonstrate what quantum computers can do for humanity.” 

Qubits and semiconductors go hand in hand

According to Dell Technologies, in the future, quantum systems will not be standalone systems, but will work together closely with classic IT systems. This means QPUs (quantum processing units) will soon make their way into conventional systems and perform selected calculations there. Classic CPUs will take over the standard tasks and support the QPUs by preparing the data and evaluating the results.

Q.ant has developed a process, for example, that enables the electronic mainframe computers of today to be enhanced by processors which use state-of-the-art quantum technology. By applying highly specialised light channels to silicon chips, this photonic chip process allows quanta to be guided and controlled almost without any losses whatsoever, even at room temperature. 

Quantum effects can also improve semiconductor electronics directly, leading to a breakthrough when it comes to the bandwidth of data transfer, energy efficiency and information security. So-called heterostructures, i.e. layered systems made from superconducting and semiconducting materials, are promising successors to today’s semiconductor ­electronics. Two suitable materials in this regard are the superconductor niobium nitride (NbN), as well as the semiconductor gallium nitride (GaN). So far, it had been uncertain, however, as to how exactly the electrons on the contact surface of these two materials behave – and if the electrons from the semiconductor might possibly disrupt the superconduction, thereby cancelling out the quantum effects. Researchers at the Paul Scherrer Institute (PSI) investigated precisely these interactions but ultimately concluded in their experiments that the electrons in each material “keep to themselves”. Vladimir Strocov, researcher at the synchrotron Swiss Light Source SLS at the PSI: “This layer system could actually create a new form of semiconductor electronics which incorporates and uses the quantum effects in superconductors.” This could bring about a new turn in semiconductor technology and make electronic components much more powerful in the future.