Reduction of charge offset drift using plasma oxidized aluminum in SETs

Area of Science:

• Quantum Computing
• Materials Science
• Nanotechnology

Background:

• Aluminum oxide (Al2O3) based single-electron transistors (SETs) are vital for quantum devices.
• Historically, Al2O3 SETs suffer from time instabilities caused by charge defects, impacting superconducting quantum computation.
• Defects in Al2O3 often dominate loss mechanisms in quantum systems.

Purpose of the Study:

• To characterize the charge offset stability of Al2O3-based SETs fabricated using in situ plasma oxidation.
• To investigate the impact of fabrication methods on defect reduction in Al2O3 tunnel barriers.
• To enable stable Al2O3-based components for quantum computing.

Main Methods:

• Fabrication of Al2O3-based SETs with sub-1 e charge sensitivity in ultra-high vacuum (UHV) chambers.
• Utilization of in situ plasma oxidation for tunnel barrier formation.
• Charge offset drift measurements to quantify device stability.

Main Results:

• Plasma oxidized Al2O3 SETs exhibit significantly reduced charge offset drift ([Formula: see text]) compared to conventionally fabricated devices.
• Best observed charge offset drift ([Formula: see text]) over [Formula: see text] days with no drift exceeding [Formula: see text].
• Improved stability attributed to reduced two-level system (TLS) defects from plasma oxidation and UHV fabrication.

Conclusions:

• In situ plasma oxidation in UHV is a superior method for fabricating stable Al2O3-based SETs.
• The reduction in TLS defects is key to enhancing the stability of Al2O3 tunnel barriers.
• These stable Al2O3 SETs are promising for applications in quantum computing and other sensitive electronic devices.