Patent ID: 8304809

Claim:
A GaN-based semiconductor device, comprising: a silicon substrate; an active layer of GaN-based semiconductor formed on the silicon substrate; a trench formed in the active layer, the trench extending from a top surface of the active layer to a depth reaching the silicon substrate; a first electrode formed on an internal wall surface of the trench, the first electrode extending from the top surface of the active layer to the silicon substrate, the first electrode being formed of metal in direct ohmic contact with both the silicon substrate and the active layer; a second electrode formed on the active layer to define a current path between the first electrode and the second electrode via the active layer in an on-state of the device; and a bottom electrode formed on a bottom surface of the silicon substrate, the bottom electrode defining a bonding pad for the first electrode, wherein the GaN-based semiconductor device is a field effect transistor further comprising: a gate electrode; a source electrode defined by the first electrode; and a drain electrode defined by the second electrode.