SEMICONDUCTOR DEVICE

PURPOSE:To obtain a stable characteristic without influences of leakage current and pulse noises by a method wherein a light emitting region or a light receiving element is formed on one main surface of a semiinsulating substrate, and a drive or amplification element of a photo element is provided on the other surface of the substrate. CONSTITUTION:The epitaxial layer 7 for the formation of an electric circuit is provided on one surface of the semi-insulting semiconductor substrate 14, and the epitaxial layers 2-6 for the formation of the laser part are provided on the other surface. Successively, an electric element is formed on the epitaxial layer 7, and then the photo element is formed by using the epitaxial layers 2-6. The electric connection between the both elements can be easily performed, if an impurity diffused region 15 is provided previously at a part of the semiconductor substrate by a thermal diffusion method, etc. In this manner, without receiving the influences by leakage current and pulse noises due to the drive or amplification element, a stable dynamic characteristic equal to the state that the light receiving or light emitting element exist at a single element can be obtained.