Provided is a semiconductor fabrication technology; and, more particularly, to a semiconductor device having a heat release structure that uses a silicon-on-insulator (SOI) substrate, and a method for fabricating the semiconductor device. The device and method of the present research provides a semiconductor device having a high heat-release structure and high heat-release structure, and a fabrication method thereof. In the research, the heat and high-frequency noises that are generated in the integrated circuit are released outside of the substrate through the tunneling region quickly by forming an integrated circuit on a silicon-on-insulator (SOI) substrate, aiid removing a buried insulation layer under the integrated circuit to form a tunneling region. The heat-release efficiency can be enhanced much more, when unevenness is formed on the surfaces of the upper and lower parts of the tunneling region, or when the air or other gases having excellent heat conductivity is flown into the tunneling region.