Abstract
This paper is a review that surveys work on the fabrication of miniature alkali vapor cells for miniature and chip-scale atomic clocks. Technology on microelectromechanical systems (MEMS) cells from the literature is described in detail. Special attention is paid to alkali atom introduction methods and sealing of the MEMS structure. Characteristics of each technology are collated and compared. The article's rhetoric is guided by the proposed classification of MEMS cell fabrication methods and contains a historical outline of MEMS cell technology development.