Integrated III-nitride devices

A III-nitride semiconductor device, comprising:

• an active III-nitride heterojunction that includes a two dimensional electron gas;
• a conductive substrate supporting said heterojunction;
• a first power electrode coupled to said heterojunction,
• a second power electrode coupled to said heterjunction;
• a third power electrode disposed between said first and said second power electrodes;
• a trench through said heterojunction under said third power electrode;
• an electrically conductive body inside said trench and electrically connected to said substrate and said third power electrode;
• a first gate arrangement between said first power electrode and said third power electrode;
• and
• a second gate arrangement between said second power electrode and said third power electrode.