A light emitting device includes a carrier, at least one epitaxial structure, at least one buffer pad and at least one bonding pad. The epitaxial structure is disposed on the carrier. The buffer pad is disposed between the carrier and the epitaxial structure, wherein the epitaxial structure is temporarily bonded to the carrier by the buffer pad. The bonding pad is disposed on the epitaxial structure, wherein the epitaxial structure is electrically connected to a receiving substrate by the bonding pad.

A light emitting device includes a carrier, at least one epitaxial structure, at least one buffer pad and at least one bonding pad. The epitaxial structure is disposed on the carrier. The buffer pad is disposed between the carrier and the epitaxial structure, wherein the epitaxial structure is temporarily bonded to the carrier by the buffer pad. The bonding pad is disposed on the epitaxial structure, wherein the epitaxial structure is electrically connected to a receiving substrate by the bonding pad.

An integrated circuit (IC) die structure comprises a substrate material comprising silicon. Integrated circuitry is over a first side of the substrate material. A composite layer is in direct contact with a second side of the substrate material. The second side is opposite the first side. The composite layer comprises a first constituent material associated with a first linear coefficient of thermal expansion (CTE), and a first thermal conductivity exceeding that of the substrate. The composite layer also comprises a second constituent material associated with a second CTE that is lower than the first, and a second thermal conductivity exceeding that of the substrate.