Transistor devices and methods of forming a transistor device

A method of forming a transistor device, the method comprising:

• forming a trench in a semiconductor structure, wherein the semiconductor structure comprises a buffer layer and a barrier layer arranged over the buffer layer, the trench extending partially into the buffer layer;
• forming a source terminal;
• forming a drain terminal;
• forming a gate terminal between the source terminal and the drain terminal, the gate terminal extending into the trench;
• forming an electrode component that comprises an electrode, the electrode component extending into the trench where the electrode component is separated from the gate terminal, wherein the electrode component contacts a side wall of the trench;
• depositing a metallic material into the trench;
• and
• etching the metallic material,
• wherein the electrode component further comprises a doped semiconductor member that contacts the side wall of the trench, and wherein the electrode comprises a metal member adjacent to the doped semiconductor member.