A micro-fluidic device comprising a semiconductor substrate attached to a fluid supply source, the substrate comprising: at least one vaporization heater (14, 42, 48, 54, 70, VH), two or more bubble pumps (16, BP) for feeding fluid from the fluid supply source (18, FS) to the at least one vaporization heater (14, 42, 48, 54, 70, VH), a fluid supply inlet from the fluid supply source (18, FS) in fluid flow communication with each of the two or more bubble pumps (16, BP), and a vapor outlet in vapor flow communication with the at least one vaporization heater (14, 42, 48, 54, 70, VH), wherein the two or more bubble pumps (16, BP) each have a fluid flow path which is in a linear shape or in an arcuate shape from the supply inlet to the at least one vaporization heater (14, 42, 48, 54, 70, VH), wherein the fluid flow paths of the two or more bubble pumps (16, BP) are arranged in a radial pattern or in a spiral pattern with respect to the at least one vaporization heater (14, 42, 48, 54, 70, VH), wherein the fluid supply source (18, FS) is disposed on a supply side of the substrate opposite from a first side of the substrate containing the at least one vaporization heater (14, 42, 48, 54, 70, VH) and the two or more bubble pumps (16, BP), wherein the fluid supply inlet is arranged through the substrate from the fluid supply side to the first side of the substrate for each of the two or more bubble pumps (16, BP), wherein each of the two or more bubble pumps (16, BP) includes a plurality of resistance heaters for moving fluid through the fluid flow path for each of the two or more bubble pumps (16, BP), and wherein a voltage pulse is applied to each of the plurality of resistance heaters in sequence so that the resistor heater forms a bubble from left to right or from right to left in the fluid flow path. at least one vaporization heater (14, 42, 48, 54, 70, VH), two or more bubble pumps (16, BP) for feeding fluid from the fluid supply source (18, FS) to the at least one vaporization heater (14, 42, 48, 54, 70, VH), a fluid supply inlet from the fluid supply source (18, FS) in fluid flow communication with each of the two or more bubble pumps (16, BP), and a vapor outlet in vapor flow communication with the at least one vaporization heater (14, 42, 48, 54, 70, VH), wherein the two or more bubble pumps (16, BP) each have a fluid flow path which is in a linear shape or in an arcuate shape from the supply inlet to the at least one vaporization heater (14, 42, 48, 54, 70, VH), wherein the fluid flow paths of the two or more bubble pumps (16, BP) are arranged in a radial pattern or in a spiral pattern with respect to the at least one vaporization heater (14, 42, 48, 54, 70, VH), wherein the fluid supply source (18, FS) is disposed on a supply side of the substrate opposite from a first side of the substrate containing the at least one vaporization heater (14, 42, 48, 54, 70, VH) and the two or more bubble pumps (16, BP), wherein the fluid supply inlet is arranged through the substrate from the fluid supply side to the first side of the substrate for each of the two or more bubble pumps (16, BP), wherein each of the two or more bubble pumps (16, BP) includes a plurality of resistance heaters for moving fluid through the fluid flow path for each of the two or more bubble pumps (16, BP), and wherein a voltage pulse is applied to each of the plurality of resistance heaters in sequence so that the resistor heater forms a bubble from left to right or from right to left in the fluid flow path.