Two research institutions have installed separate advanced fabrication systems designed to study and improve the materials used in quantum computing components. The systems, located at the Massachusetts Institute of Technology (MIT) and Lawrence Berkeley National Laboratory (Berkeley Lab), are focused on addressing materials-related challenges in the development of qubits.
MIT.nano Installation
A custom-built molecular beam epitaxy (MBE) system has been installed in the first-floor cleanroom of MIT.nano. The system was manufactured by DCA and, according to the company, represents the largest single deposition chamber (1-meter diameter) sold by the company in the United States. The equipment occupies 600 square feet. Funding for the purchase was provided through grants from the Army Research Office (ARO) and the Laboratory for Physical Sciences (LPS).
Purpose and Capabilities
The system is designed to investigate materials science and fabrication engineering related to reducing sources of environmental noise in superconducting qubits. It enables study of how film growth affects material properties used in qubit fabrication.
The MBE system comprises six chambers:
- Load lock
- Distribution center
- Deposition (growth) chamber
- Oxidation chamber
- Storage chamber (holds up to 10 wafers)
- X-ray photoelectron spectroscopy (XPS) chamber
The XPS chamber allows researchers to measure changes in material structure without breaking vacuum, enabling analysis of buried interfaces. The system operates under ultra-high vacuum conditions.
Statements
William D. Oliver, a professor at MIT, stated that most improvements to superconducting qubit performance have resulted from circuit design. He added that "going forward, we need to address the fundamental materials science."
Patrick Strohbeen stated that understanding the materials platform represents "the last piece of the puzzle" and noted that buried interfaces have been "understudied."
Berkeley Lab's QIS Cluster Tool
Lawrence Berkeley National Laboratory has introduced a robotic system known as the quantum information science (QIS) cluster tool. The system is located within a cleanroom at the Molecular Foundry, a U.S. Department of Energy (DOE) user facility.
System Functionality
The QIS cluster tool integrates multiple fabrication and analysis instruments into a single closed vacuum system. This design enables researchers to grow and layer materials using techniques including atomic layer deposition, sputtering, evaporation, and etching without exposure to external contamination. A robotic arm at the tool's center moves 8-inch wafers between stations. The automation standardizes the process and enables fine-tuning of material recipes.
Applications and Capabilities
The tool is designed to develop Josephson junctions, a component in many quantum computers. Josephson junctions consist of two superconductors separated by an ultrathin insulating layer, allowing electrons to tunnel through the barrier. Combining Josephson junctions with other components forms circuits that act as qubits.
The system's precision allows for creation of features a few atoms wide. It includes analysis tools using electrons, x-rays, lasers, and infrared light to identify materials and impurities.
Data Collection and AI Integration
The QIS cluster tool automatically collects data during quantum device fabrication. According to Berkeley Lab, this data can be used to train artificial intelligence (AI) models, helping correlate fabrication processes with qubit performance.
Research Applications
Researchers at the Molecular Foundry have used the tool to create high-quality aluminum Josephson junctions and explore materials such as hafnium, which has shown potential for qubit-based particle detectors, including dark matter searches.
According to Berkeley Lab, the system prioritizes basic scientific exploration of materials and their properties, unlike typical industrial cluster tools focused on production. Discoveries made using the system will be publicly shared.
Beyond qubits, the tool can develop components for microelectronics, resonators, capacitors, and sensors for applications including dark matter detection, single-molecule sensing, and virus identification.