Low temperature, wafer-level process of alkali-metal vapor cells for micro-fabricated atomic clocks

We propose a low temperature process of alkali-metal vapor cells for microfabricated atomic clocks using alkali-metal source tablets (AMSTs) as alkali metal dispensers. An AMST contains precise quantities of cesium aside (CsN3) inside the porous alumina that is used to produce of Cs by thermal decomposition of CsN3. The AMST technology together with sequential plasma activated Si/glass bonding is a combination of technology that enables the low temperature wafer-level process of Cs vapor cells, resulting good quality of spectroscopic measurement for atomic clocks. The short-term frequency stability obtained with the fabricated cell was measured to be 2 × 10−11 at an integration time of 1 sec.