NOVELTY - The method (100) involves providing (102) a GaN workpiece. Multiple particles are introduced (106) into a surface of the GaN workpiece, in order to form a cleave region in the GaN workpiece. The surface of the GaN workpiece is bonded (108) to a substrate. The energy is applied to cleave (110) a detached thickness of GaN from a remainder of the GaN workpiece. The substrate bearing the detached thickness of GaN is processed. The substrate is provided with the molybdenum, tungsten, aluminum nitride and sapphire.    USE - Method for forming substrate such as silicon-on-insulator substrate of optoelectronic device such as LED and laser using layer transfer technique. Can also be used for photonic or photovoltaic device, piezoelectronic device, flat panel display, microelectromechanical system, nano-technology structure, sensor, actuator, integrated circuit, biomedical device, solar cell, etc.    ADVANTAGE - By using a thin high-quality GaN layer for homoepitaxial growth, a reduction in lattice mismatch is achieved. The defects of low incidence of threading dislocation density (TDD) are also achieved. Since the metal substrate is engineered to match the GaN layer through the epitaxial growth temperature, a CTE mismatch induced layer stresses, cracks and defects are eliminated. By using metal substrate and thermally or electrically conductive internal layers, high electrical and thermal conductivity substrates are realized. Hence the higher external quantum efficiency (EQE) and higher wall plug efficiency (WPE) are achieved. The necessity of the certain back-end manufacturing steps such as laser lift-off is also eliminated. An optical efficiency is also enhanced.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for an apparatus for forming substrate of optoelectronic device.    DESCRIPTION OF DRAWING(S) - The drawing shows a flow diagram illustrating the method for forming substrate for optoelectronic device.    Process flow for forming substrate (100)    Step for providing GaN workpiece (102)    Step for introducing particle into surface of GaN workpiece (106)    Step for bonding surface of GaN workpiece to substrate (108)    Step for cleaving detached thickness of GaN (110)