An LED module includes a housing, a support member disposed in the housing and having a lower portion supporting a reflective plate thereabove, and a cone-shaped protrusive portion projecting upwardly from the lower portion to support a diffusing plate thereabove so as to prevent the occurrence of downward bending of the middle portions of the reflective and diffusing plates due to their weights. The ducts or segments may be part of an air duct system that comprises a primary air duct, at least one secondary air duct, and at least one branch duct. The bottom layer serves as a seed layer for the center layer, which is alpha tantalum, while the third, topmost, layer is selected for its smoothness, its compatibility with the inter-layer dielectric materials, and its ability to protect the underlying tantalum.