A printhead is provided having a plurality of chambers on a substrate, each chamber having a nozzle, a heater arranged in each chamber so as to heat fluid within the chamber to form a gas bubble therein and thereby cause ejection of a drop from the corresponding nozzle, and a plurality of passages formed in the substrate so that each passage supplies the fluid to an associated one of the chambers. Each heater includes solid material and has a mass of less than 10 nanograms of the solid material, which is configured to be heated to cause formation of the gas bubble.