The present invention provides a semiconductor device formed with a diode array together with bipolar transistors, which is capable of preventing the occurrence of crystal defects developed in cross patterns in deep trench regions and improving device yields, and a method of manufacturing the semiconductor device. A semiconductor device includes a LOCOS oxide film which isolates a plurality of diodes in an X direction, and deep trenches which isolate the plurality of diodes in a Y direction. The depth of each of the deep trenches is deeper than a high density layer embedded below a collector layer of each bipolar transistor. A shallow trench may be used as an alternative to the LOCOS oxide film.