Wafer-level integration of micro heaters on an alkali vapor cell for chip-scale atomic magnetometers

Abstract

Wafer-level integration of micro heater on an alkali vapor cell for chip-scale SERF magnetometers is presented. In order to obtain a suitable resistivity, polysilicon and aluminum are mixed as the target material. Magnetron sputtering is adopted to fabricate the heater on the surface of the alkali vapor cell. Various voltages are applied to the heater, of which the temperatures are measured by thermal sensitive sensors. Spin exchange relaxation free (SERF) atomic magnetometer with the heater integrated on the alkali vapor cell is characterized. Results show that the micro heater is successfully integrated on the alkali vapor cell. With the integrated heater, the rubidium vapor cell is heated up to 120°C by a 445kHz AC current. The sensitivity of the SERF magnetometer is 6.3pT/Hz1/2. Results also indicate that it provides an effective and low-cost solution for the miniaturization of atomic magnetometers.