III-nitride based semiconductor structure with multiple conductive tunneling layer

A semiconductor structure comprising:

• a substrate;
• a conductive carrier-tunneling layer over the substrate, the conductive carrier-tunneling layer comprising:
• first group-III nitride (III-nitride) layers formed of aluminum gallium nitride (AlGaN) and having a first bandgap, wherein the first III-nitride layers have first thicknesses;
• and
• second III-nitride layers indium gallium nitride (InGaN) and having a second bandgap lower than the first bandgap, wherein the first III-nitride layers and the second III-nitride layers are stacked in an alternating pattern, and wherein the second III-nitride layers have second thicknesses greater than the first thicknesses;
• and
• an active layer over the conductive carrier-tunneling layer.

A semiconductor structure comprising:

• a silicon substrate formed of a silicon-containing material;
• a conductive carrier-tunneling layer over and contacting the silicon-containing material of the silicon substrate, the conductive carrier-tunneling layer comprising:
• a plurality of first group-III nitride (III-nitride) layers formed of a same first material and having a first bandgap, wherein the plurality of first III-nitride layers have substantially a same first thickness;
• and
• a plurality of second III-nitride layers formed of a same second material and having a second bandgap lower than the first bandgap, wherein the plurality of first III-nitride layers and a plurality of second III-nitride layers are stacked in an alternating pattern, wherein the silicon-containing material of the silicon substrate contacts one of the plurality of the first and the second III-nitride layers, and wherein the second III-nitride layers have substantially a same second thickness greater than the same first thickness;
• a third III-nitride layer over the conductive carrier-tunneling layer;
• an active layer over the third III-nitride layer;
• and
• a fourth III-nitride layer over the active layer, wherein the third III-nitride layer and the fourth III-nitride layer are of opposite conductivity types.