A micro-fluidic device. The device includes a semiconductor substrate attached to a fluid supply source. The substrate contains at least one vaporization heater, one or more bubble pumps for feeding fluid from the fluid supply source to the at least one vaporization heater, a fluid supply inlet from the fluid supply source in fluid flow communication with each of the one or more bubble pumps, and a vapor outlet in vapor flow communication with the at least one vaporization heater. The one or more bubble pumps each have a fluid flow path selected from a linear path, a spiral path, a circuitous path, and a combination thereof from the supply inlet to the at least one vaporization heater.