Electrodes for semiconductor devices and methods of forming the same

A III-N transistor, comprising:

• a III-N material structure;
• a source and a drain;
• an electrode-defining layer having a thickness, the electrode-defining layer being over a surface of the III-N material structure, the electrode-defining layer having a recess with a first sidewall proximal to the drain and a second sidewall proximal to the source, the first and second sidewalls each comprising a plurality of steps;
• and
• an electrode in the recess, the electrode including an extending portion at least partially over the first sidewall;
• wherein
• the first sidewall forms a first effective angle relative to the surface of the III-N material structure and the second sidewall forms a second effective angle relative to the surface of the III-N material structure, the second effective angle being larger than the first effective angle;
• the electrode includes a gate in a gate region of the transistor;
• the plurality of steps in the first and second sidewalls each include a first step having a first step width directly adjacent to the gate, a second step having a second step width directly adjacent to the first step, and a third step having a third step width directly adjacent to the second step;
• a ratio of the first step width to the second step width in the plurality of steps in the first sidewall is substantially the same as a ratio of the first step width to the second step width in the plurality of steps in the second sidewalk;
• and
• a sum of the first step width, the second step width, and the third step width in the first sidewall is greater than a sum of the first step width, the second step width, and the third step width in the second sidewall.