Intel and QuTech make qubits on process line for the first time
Two weeks ago, Photon Box reported that Intel demonstrated their technology for making qubits using a semiconductor process line at the APS March conference. Now, Intel has published their research results in the journal Nature Electronics, and the paper "Qubits made by advanced semiconductor manufacturing"[1] has appeared on the cover of the journal.
The research was carried out by Intel in collaboration with QuTech, a Dutch quantum technology agency. A QuTech press release announced that Intel engineers and QuTech scientists have fabricated the first qubits on the same process line that mass-produces conventional computer chips. This advancement has become a long-term goal due to its promise of scalability. The breakthrough is a critical step toward the thousands of qubits needed for practical quantum computing.
There are several major obstacles to the production of scalable quantum computers, and finding the right type of qubit is one of them. A promising candidate qubit is based on the spins of individual electrons trapped in silicon nanodevices. A major advantage of this device is that it resembles a conventional transistor. Therefore, it is expected to utilize the extensive knowledge and skills of the semiconductor industry to produce qubit devices with unprecedented yield, high uniformity, and few defects.
The cover of Nature Electronics, March 2022 Vol. 5 No. 3.
From flexible cleanrooms to strict factories
Currently, semiconductor qubit chips are typically fabricated in cleanrooms using tools that are optimized for flexible design changes and quick turnaround, but compromise reliability. On the other hand, industrial semiconductor manufacturing is very reliable, but strict design rules must be followed. Important open questions are whether qubit designs are manufacturable within design rules, and whether qubits can withstand processing conditions to achieve extremely high yields.
High-volume experiments
Anne-Marije, first author of the paper and a PhD researcher at QuTech, said: "Industrial manufacturing techniques are different from those typically used to make samples of such quantum dots, as if we originally wrote in calligraphy, and now we have switched to a stencil machine. The former offers greater flexibility, the latter offers significant improvements in yield and consistency. Also, instead of making 20 devices at a time, a manufacturing cycle can now produce thousands of devices, allowing us to Gather statistics on device properties." In addition, important qubit properties, such as lifetime, are among the highest measured for these types of qubits.
The advantages of semiconductor qubits
Lieven Vandersypen, QuTech's chief scientist, added: "Many articles have stated that semiconductor spin qubits in silicon are compatible with CMOS semiconductor fabrication. But until now, we have not been able to prove that this is true." Furthermore, he said, "The Intel team An unprecedented 98 percent yield was achieved, compared to 50 percent in our university clean room."
Qubits in semiconductor quantum dots
The type of quantum information that makes up this qubit is the electron spin. The electrons are trapped in a "box" fed by a potential well called a quantum dot in the energy landscape. The energy landscape is created by a combination of material properties (similar to the layout of conventional transistors: a silicon-silicon oxide interface) and an electric field. This makes it possible to isolate and localize individual electrons in quantum dots and to fully control their spins.
Next steps
Industrial fabrication of single-qubit devices is now a reality. The next effort is to control multiple spin qubits and improve the quality of qubit control. Combined, these advances will provide a solid foundation for full-scale quantum computing that integrates millions of qubits.
Link:
https://qutech.nl/2022/03/29/intel-qutech-first-industrially-manufactured-qubit/
