Patent ID: 8461626

Claim:
A hetero-structure field effect transistor, comprising: a first contact and a second contact; a hetero-junction structure, said hetero-junction structure including: a first layer made from a first semiconductor material; a second layer made from a second semiconductor material; and an interface at which said first layer and said second layer are in contact with each other; a two dimensional electron gas is formed in a part of said first layer directly adjacent to said interface, for propagating of electrical signals from the first contact to the second contact or vice versa; said transistor further including: a gate structure for controlling a conductance of a path through the hetero-junction structure, between the first contact and the second contact; a substrate layer including a silicon carbide layer and a silicon layer, said silicon layer being bonded to said silicon carbide layer by an electrically isolated bonding layer, and wherein said first layer is provided on said silicon layer; and a dielectric layer separating said first layer from said substrate layer; said second contact includes an electrical connection between said substrate layer and said first layer, said electrical connection including a passage through at least said dielectric layer, said passage being filled with an epitaxial doped semiconductor material which is electrically connected to the first layer, said epitaxial doped semiconductor material having a higher conductivity than said first semiconductor material.