Semiconductor device and method of manufacturing semiconductor device

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

• preparing a semiconductor substrate having a main surface;
• forming a device structure at the main surface of the semiconductor substrate;
• forming an interlayer insulating film on the main surface of the semiconductor substrate, the interlayer insulating film covering the device structure;
• forming a contact hole from an upper surface of the interlayer insulating film, to penetrate through the interlayer insulating film in a depth direction of the semiconductor device and to form a recess at the main surface of the semiconductor substrate, the contact hole exposing a portion of the device structure, and having:
• a side wall, and
• a bottom that is configured by the recess at the main surface of the semiconductor substrate;
• sequentially forming a titanium film and a titanium nitride film, as a barrier metal, along an inner wall of the contact hole;
• performing a heat treatment thereby causing the titanium film at the bottom of the contact hole and the semiconductor substrate to react with each other, thereby forming a titanium silicide film in the semiconductor substrate along an inner wall of the recess;
• performing a chemical vapor deposition thereby depositing a tungsten film on the barrier metal in the contact hole, thereby embedding the tungsten film in the contact hole;
• and
• forming a metal electrode containing aluminum, on the interlayer insulating film and the tungsten film, wherein
• after the heat treatment, in the depth direction of the semiconductor device, an upper surface of the titanium nitride film at the bottom of the contact hole is closer to the interlayer insulating film than is the main surface of the semiconductor substrate.