SEMICONDUCTOR DEVICE

Provided is a semiconductor device, which has a wiring structure including a single-layer diffusion barrier layer having both a diffusion barrier function and a liner function. The semiconductor device has a wiring structure including an insulating layer, a conductive wiring, and a diffusion barrier layer disposed between the insulating layer and the conductive wiring in a manner of being in contact with both the insulating layer and the conductive wiring. The diffusion barrier layer is made of an alloy having an amorphous structure containing a first metal and a second element in an amount of 90% by mass or more in total. The first metal is any one selected from Co, Ru, and Mo. The second element is one or two or more selected from Zr, Al, and Nb when the first metal is Co, the second element is Zr when the first metal is Ru, and the second element is one or two selected from Y and B when the first metal is Mo.