An inkjet printhead that has a nozzle layer defining an array of nozzle apertures and a substrate for supporting the nozzle layer, the substrate defining a flow path for an ejectable liquid to each nozzle. Each nozzle aperture has an associated heater element positioned for heating the ejectable liquid above its boiling point to form a vapor bubble to eject a drop of the ejectable liquid through the nozzle aperture. The nozzle aperture is less than 5 microns thick in the drop ejection direction.