Microfabrication of Alkali Vapor Cells with Lower the Outgassing and Temperature Utilizing Silicon 3D Structure

Abstract

We report an effective Cs vapor cell fabrication at the wafer-level utilizing a novel Cs-source, that are applicable to MEMS-based atomic clocks. In this method, a microfabricated Si grooves with multiple re-entrant structures (i.e., “micro-size” scalloped patterns) is employed as a preform, and CsN3 precursor is deposited on the surface. This method enables in-situ thermal decomposition of CsN3 with high efficiency at the wafer-level. The fabricated Cs-filled cells via a combination of the Cs-source and low-temperature bonding process achieved the good atomic clock frequency stability. Furthermore, the residual gas analysis data demonstrated that the Si preform enables low residual gasses in the cell, leading to enhance long-term stability of the Cs density.