  We describe micro-fabricated rubidium vapor cells with integrated
temperature-control functionality and demonstrate their suitability for use in
miniaturized ultra-sensitive magnetometers. These functionalized vapor cells
(FVCs) embody a dual-chamber design in low-conductivity silicon with
anti-permeation coatings and micro-structured thin-film platinum surface traces
as resistive heaters and temperature sensors. Thermal tests show our ability to
control alkali metal distribution within the FVCs, ensuring a clean sensing
chamber for optical measurements. Optical absorption spectroscopy is used to
correlate the temperature readings with vapor density and to measure buffer gas
pressure, of interest for optimizing sensitivity. Finally, we demonstrate
zero-field resonance magnetometry with 18 fT/Hz$^{1/2}$ sensitivity in the 10
Hz to 100 Hz band, limited by laser noise and magnetic shield noise, which
indicates that the functionalization does not introduce significant magnetic
noise.
