ZHONG Z Q,DU T,LI X H,et al. Research on vacuum chamber of chip-scale atomic beam clocks[J]. Vacuum and Cryogenics,2025,31(3):412−418. DOI: 10.12446/j.issn.1006-7086.2025.03.018
Citation: ZHONG Z Q,DU T,LI X H,et al. Research on vacuum chamber of chip-scale atomic beam clocks[J]. Vacuum and Cryogenics,2025,31(3):412−418. DOI: 10.12446/j.issn.1006-7086.2025.03.018

Research on Vacuum Chamber of Chip-scale Atomic Beam Clocks

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  • Received Date: March 21, 2025
  • Accepted Date: May 12, 2025
  • As two commonly used time-frequency reference devices today, the well-developed microwave atomic beam clocks have the disadvantages of large size and high-power consumption, while the chip-scale coherent population trapping (CPT) atomic clocks have poor long-term operational stability. In recent years, a series of technological advancements including laser cooling, photon integration, and vacuum technology have made it possible to miniaturize atomic beam clocks. Chip-scale atomic beam clocks are entirely fabricated by advanced MEMS technologies. They combine the high frequency stability of existing microwave atomic beam clocks with the small size and low power consumption of CPT chip atomic clocks, providing excellent comprehensive advantages. However, there have been few reports on chip-scale atomic beam clocks in China so far. Key preparation technologies of the vacuum chamber for chip-scale atomic beam clocks are systematically studied, including microfabrication of beam source cavity, beam drift cavity, and micro collimation channel array, as well as high airtightness packaging of multi-layer micro vacuum chamber structures. Based on optimized deep reactive ion etching technologies, common problems of undercutting and poor process controllability in wet chemical silicon corrosion process have been avoided, and high aspect ratio micro collimation channel arrays with steep sidewalls, smooth surfaces, and precise dimensions are obtained. Through the overall optimization of intermediate electrode extraction technology and anode bonding process, the damage of reverse electric field to the formed bonding interfaces during multi-layer bonding process has been reduced and weakened, and a high-quality five-layer bonding structure of glass and silicon is achieved. This study has laid the basic process foundation for realizing high-frequency stable chip-scale atomic beam clocks and other quantum device systems.

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