An illustrative method includes providing a semiconductor structure. The semiconductor structure includes an active region and an electrically insulating structure. The active region includes a source region, a channel region and a drain region. The electrically insulating structure includes a recess over the channel region. A work function adjustment layer is deposited over the semiconductor structure. A portion of the work function adjustment layer is deposited at a bottom surface of the recess. The work function adjustment layer includes at least one material other than titanium nitride. A titanium nitride pre-wetting layer is deposited over the work function adjustment layer. A titanium wetting layer is deposited directly on the titanium nitride pre-wetting layer. After the deposition of the titanium wetting layer, the recess is filled with aluminum.