Semiconductor device and manufacturing method of the same

A semiconductor device including a substrate comprising:

• a MOS transistor provided on one side of said substrate;
• and
• a double poly-silicon bipolar transistor provided on the other side of said substrate, said bipolar transistor comprising:
• a semiconductor layer in which a base take-out electrode and an emitter take-out electrode are different, and
• said MOS transistor comprising:
• a gate oxide film formed above said substrate,
• a gate electrode formed directly above said gate oxide film,
• a first silicon oxide insulating film disposed directly on said gate electrode;
• a silicon nitride insulating film disposed directly on said first silicon oxide insulating film,
• a second silicon oxide insulating film disposed directly on said silicon nitride insulating film;
• and
• a barrier metal including titanium material formed directly above said second silicon oxide film;
• said semiconductor device having an opening from which at least said silicon nitride insulating film is removed above substantially all of an element isolating region for isolating said MOS transistor from said bipolar transistor.