(QuTech) QuTech’s newsroom announced that engineers from Intel and scientists from QuTech have delivered the first qubit made in the very same industrial manufacturing facilities that mass-produce conventional computer chips. Inside Quantum Technology brings you the announcement below.
Intel and QuTech achieved this major technological feat through close collaboration and extensive knowledge sharing. This advancement has been a long-standing goal due to its promise of scalability. The breakthrough is a crucial step towards scaling to the thousands of qubits that are needed for practical quantum computation. The investigators published their results in Nature Electronics (DOI).
For a full five years the scientists from QuTech and the researchers at Intel worked together to achieve their goal. This called for the alignment of two very different worlds. “Our objective of getting a qubit onto silicon meant that we had to work to an extreme level of precision. For Intel the novelty was to put various electrodes alongside each other on such a small scale and in two layers,” says QuTech’s Anne-Marije Zwerver.
Currently, semiconductor qubit chips are typically fabricated in cleanrooms using tools that are optimized for flexible design changes and fast turnaround, but compromise on reliability. Industrial semiconductor manufacturing, on the other hand, is extremely reliable but is bound to strict design rules. Important open questions were whether the qubit designs were in fact manufacturable within the design rules and whether the qubits would survive the processing conditions to achieve extremely high yield.
“Industrial manufacturing techniques are different from the techniques that are typically used to fabricate such quantum dot samples,” says Anne-Marije, first author and PhD researcher at QuTech—a collaboration between the TU Delft and TNO. “It was as if we were first writing with calligraphy and now, we changed to a stencil machine. The former gives more flexibility, the latter gives a significant improvement in yield and uniformity. Moreover, instead of making 20 devices at a time, a fabrication round now gives us tens of thousands of devices, allowing us to collect statistics on the device properties.”
The type of quantum information that makes this qubit is the electron spin. The electron is trapped inside a “box”, given by a potential well in an energy landscape, called a quantum dot. The energy landscape is produced by a combination of material properties (similar layouts to a conventional transistor: silicon–silicon oxide interface) and electric fields. In this way it is possible to isolate and address a single electron in the quantum dot and have full control over its spi.
The industrial manufacturing of a single qubit device is now a fact. Parallel efforts are geared towards controlling multiple spin qubits and improving the quality of the qubit control. Combined, these advances will build a solid foundation to realize full-scale quantum computing integrating millions of qubits.