Interconnects for semiconductor devices are formed by forming a reaction control layer on a lower conductive layer of a semiconductor device, forming a reactive metal layer on the reaction control layer, opposite the lower conductive layer, reacting the lower conductive layer with the reactive metal layer, through the reaction control layer, to form an ohmic contact for the semiconductor device, and forming an upper conductive layer on the ohmic contact, opposite the lower conductive layer. Interconnects so formed may provide reduced contact resistance and reduced agglomeration of the ohmic contact region, independent of reaction temperatures. The reactive metal layer is preferably a refractory metal and the reaction control layer is preferably a refractory metal compound. The upper conductive layer is also preferably a refractory metal.