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PROCESS FOR FABRICATING COMPACT ALKALI VAPOR CELLS WITH AN ON-WAFER ALKALI SOURCE

Patent Number: 11,180,844

Abstract

We describe a method for fabricating millimeter-scale and sub-millimeter calls containing a vapor of alkali atoms in large numbers at the wafer scale. The key element of the method is that the wafer that forms the glass lid of the cell is translated laterally between the alkali deposition step and the final bonding step. This translation step allows the source of alkali atoms to be integrated as part of one of the wafers and hence removes the need to have a separate alkali atom source, which can be complicated to implement.

patent description

Making alkali metal vapor cells includes: providing a preform wafer that includes cell cavities in a cavity layer; providing a sealing wafer having a cover layer and transmission apertures; disposing a deposition assembly on the sealing wafer; disposing an alkali metal precursor in the deposition assembly; disposing the sealing wafer on the preform wafer; aligning the transmission apertures with the cell cavities; subjecting the alkali metal precursor to a reaction stimulus; producing alkali metal vapor in the deposition assembly; communicating the alkali metal vapor to the cell cavities; receiving, in the cell cavities, the alkali metal vapor from the transmission apertures; producing an alkali metal condensate in the cell cavity; moving the sealing wafer such that the cover layer encapsulates the alkali metal condensate in the cell cavities; and bonding the sealing wafer to the preform wafer to make individually sealed alkali metal vapor cells in the preform wafer.

Created September 13, 2022, Updated September 15, 2022