Intel announced the release of Tunnel Falls, a 12-qubit silicon chip, fabricated on 300mm wafers in Intel's D1 fabrication facility in Oregon, US. According to Intel, Tunnel Falls is the first chip publicly announced by Intel based on silicon spin qubits. The device leverages its most advanced CMOS fabrication capabilities, including the use of extreme ultraviolet (EUV) lithography. Intel also reports a 95% yield rate across the wafer, in addition to voltage uniformity similar to a CMOS logic process. Each wafer provides over 24,000 quantum dot devices.
"The release of the new chip is the next step in Intel's long-term strategy to build a full-stack commercial quantum computing system," indicated Jim Clarke, director of Quantum Hardware at Intel.
Intel has long belived that silicon spin qubits are superior to other qubit technologies because of their synergy with leading-edge transistors. Being the size of a transistor also means that silicon spin qubits are up to 1 million times smaller than other qubit types measuring approximately 50 nanometers by 50 nanometers.
In the context of a silicon electron spin device, silicon is employed to host and manipulate the spin of individual electrons. The device structure involves quantum dots, which are small nanoscale regions within the silicon that can confine electrons and control their spin behavior. A major advantage of this device is its resemblance to conventional transistors.
While silicon spin qubits are typically presented on one device, Intel's research demonstrates success across an entire wafer. Back in October 2022, in a research conducted using its second-generation silicon spin test chip, Intel already demonstrated what it claimed to be the industry's highest reported yield and uniformity to date of silicon spin qubit devices.
Through testing the devices using the Intel cryoprober, a quantum dot testing device that operates at cryogenic temperatures ( -271.45 degrees Celsius), Intel's research isolated 12 quantum dots and four sensors. This result represents the industry's largest silicon electron spin device with a single electron in each location across an entire 300 millimeter silicon wafer, according to Intel.
In the October 2022 demonstration, Intel reported uniformity with a 95% yield rate across the wafer. The increased yield and uniformity in devices allows Intel to use statistical process control to identify areas of the fabrication process to optimize. Intel indicated that this accelerated learning and marked a crucial step toward scaling to the thousands or potentially millions of qubits required for a commercial quantum computer.
In addition, the use of the cryoprober together with software automation enabled more than 900 single quantum dots and more than 400 double dots at the last electron, which can be characterized at one degree above absolute zero in less than 24 hours.
Following the release of Tunnel Falls, Intel will work to improve the performance of the chip and integrate it into its full quantum stack with the Intel Quantum Software Development Kit (SDK). According to Intel, it is already developing its next-generation quantum chip based on Tunnel Falls; it is expected to be released in 2024. In the future, Intel plans to partner with additional research institutions globally to build the quantum ecosystem.
