Carrier Substrate

This invention provides a carrier or submount for high power devices packaging and a method for forming the carrier or submount. The carrier comprises a thermal conductive ceramic substrate, a patterned adhesion layer on the substrate, a heat dissipation layer on the patterned adhesion layer, a conformal cover layer enclosing the heat dissipation layer and the adhesion layer, a lateral heat dissipation layer on the substrate and between the cover layer on the first region and the cover layer on the second region, a diffusion barrier layer on the conformal cover layer, and an eutectic bonding layer on the diffusion barrier layer. The substrate includes a first region for bonding high power device, a second region for wire-bonding, and a third region for heat sink. The first region and second region are on a first surface of the substrate, and the third region is one the second surface, opposite to the first surface, of the substrate.