Thermal fluid-ejection echanism having heating resistor on cavity sidewalls

A thermal fluid-ejection mechanism comprising:

• a substrate having a top surface and defining a cavity having one or more sidewalls and a floor, the sidewalls at an angle of greater than or equal to nominally ninety degrees from the floor;
• a conductor comprising a patterned conductive layer on one or more of the top surface of the substrate and the sidewalls of the cavity;
• and,
• a heating resistor comprising a patterned resistive layer on just the sidewalls and not on the floor of the cavity, the patterned resistive layer located over the patterned conductive layer where the patterned conductive layer is on the sidewalls of the cavity,
• wherein electrical activation of the heating resistor via the conductor causes fluid to be ejected from the thermal fluid-ejection mechanism.

A thermal fluid-ejection device comprising:

• a plurality of thermal fluid-ejection mechanisms to thermally eject fluid in drops, each thermal fluid-ejection mechanism comprising a ring-type heating resistor;
• and,
• a controller to control thermal ejection of the fluid by the thermal fluid-ejection mechanisms,
• wherein each thermal fluid-ejection mechanism comprises:
• a substrate having a top surface and defining a cavity having one or more sidewalls and a floor, the sidewalls at an angle of greater than nominally ninety degrees from the floor;
• a conductor comprising a patterned conductive layer on one or more of the top surface of the substrate and the sidewalls of the cavity;
• and,
• a heating resistor comprising a patterned resistive layer on just the sidewalls and not on the floor of the cavity, the patterned resistive layer located over the patterned conductive layer where the patterned conductive layer is on the sidewalls of the cavity.