The present application discloses two-phase cooling devices that may include at least three substrates: a metal with a wicking structure, an intermediate substrate and a backplane. A fluid may be contained within the wicking structure and vapor chamber for transporting thermal energy from one region of the thermal ground plane to another region of the thermal ground plane, wherein the fluid may be driven by capillary forces within the wicking structure. The intermediate substrate may form narrow channels within the wicking structure, providing high capillary forces to support large pressure differences between the liquid and vapor phases, while minimizing viscous losses of the liquid flowing in the wicking structure.