Middle layer of die structure that comprises a cavity that holds an alkali metal

摘要

In one implementation, a chamber is selected that accommodates an array of die structures that comprises one or more cavities. An inner chamber of the chamber is maintained at a first temperature. An alkali metal source of the chamber is maintained at a second temperature greater than the first temperature. An outer chamber of the chamber is maintained at a third temperature greater than the first temperature and the second temperature. The one or more cavities of the array of die structures are filled with a portion of the alkali metal source. The one or more cavities of the array of die structures are sealed to comprise the portion of the alkali metal source.