Integrated power device on a semiconductor substrate having an improved trench gate structure

A power device comprising:

• a semiconductor substrate having at least one trench therein defining sidewalls and a bottom;
• a first insulating material coating layer extending along said sidewalls and said bottom of said at least one trench;
• a conductive gate structure in said at least one trench;
• wherein said conductive gate structure comprises a second conductive coating layer comprising a first conductive material extending along said sidewalls of said at least one trench, and a conductive central region comprising a second conductive material being interconnected to said second conductive coating layer, the second conductive material having a different resistivity than said first conductive material;
• and
• a plurality of contact areas along said sidewalls of said at least one trench and between said second conductive coating layer and said conductive central region, respective insulating elements separating adjacent ones of said plurality of contact areas, and said plurality of contact areas being filled in with said second conductive material.