Method of manufacturing semiconductor device

A method of manufacturing a semiconductor device, the method comprising:

• preparing a semiconductor substrate having a main surface, a single crystal silicon region formed in the semiconductor substrate, and a polycrystalline silicon region formed on the semiconductor substrate at the main surface;
• as a first process, forming an interlayer insulating film covering the single crystal silicon region and the polycrystalline silicon region;
• as a second process, forming in the interlayer insulating film, a plurality of first contact holes exposing the single crystal silicon region and a second contact hole exposing the polycrystalline silicon region;
• as a third process, performing an ion implantation of a dopant in the single crystal silicon region, at portions thereof exposed by the plurality of first contact holes;
• as a fourth process, using the interlayer insulating film as a mask and etching the single crystal silicon region and the polycrystalline silicon region, thereby concurrently forming a plurality of first contact trenches respectively continuous with the plurality of first contact holes and a second contact trench continuous with the second contact hole;
• as a fifth process, forming a first electrode electrically connected to the single crystal silicon region at an inner wall of each of the plurality of first contact trenches;
• and
• as a sixth process, forming a second electrode electrically connected to the polycrystalline silicon region at an inner wall of the second contact trench.