Semiconductor device with metal structure electrically connected to a conductive structure

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

• forming a plurality of source regions at a first major surface of a semiconductor die comprising the first major surface and an opposite second major surface;
• forming a plurality of gate electrodes at the first major surface, each of the plurality of gate electrodes being proximate with two other source regions of the plurality of source regions;
• forming a common drain region at the second major surface;
• forming a common auxiliary layer stack over the first major surface, the common auxiliary layer stack directly contacting each of the plurality of source regions, wherein forming the common auxiliary layer stack comprises:
• forming a metal diffusion barrier layer, and
• forming an adhesion layer over the metal diffusion barrier layer, wherein the adhesion layer comprises a first metal and a second metal different from the first metal;
• and
• forming a common metal structure over the common auxiliary layer stack, the common metal structure comprising the first metal, wherein the common metal structure directly contacts the adhesion layer.

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

• forming a source region at a first major surface of a semiconductor substrate comprising the first major surface and an opposite second major surface;
• forming a trench extending into the semiconductor substrate from the first major surface, wherein a first mesa and a second mesa are formed around the trench;
• forming a gate electrode in the trench;
• forming an auxiliary layer stack over the first major surface, the auxiliary layer stack directly contacting the source region, the auxiliary layer stack comprising a barrier layer and an adhesion layer disposed over the barrier layer, the adhesion layer comprising a first metal and a second metal different from the first metal;
• forming a metal structure, directly contacting the adhesion layer, over the auxiliary layer stack, the metal structure comprising the first metal;
• and
• forming a drain region at the second major surface.