An inkjet printhead is provided having a substrate defining inlet passages, sidewalls extending from the substrate, and a nozzle plate supported by the sidewalls and defining nozzle apertures. The nozzle plate, the sidewalls and the substrate define chambers. The printhead further has a heater element suspended within each of the chambers. The heater element has a planar structure parallel to the plane of the nozzle plate, and a spacing between the heater element and each sidewall of the chamber is between 0.1 microns and 20 microns. The heater element heats a liquid in the chamber to form a gas bubble. The gas bubble causes the ejection of a drop of the liquid through the nozzle aperture.