Semiconductor device and method for manufacturing same
There are provided a high current semiconductor device that has low on-resistance, high mobility, and good pinch-off characteristics and in which a kink phenomenon is not easily caused even if a drain voltage is increased, and a method for producing the semiconductor device. The semiconductor device of the present invention includes a GaN-based layered body 15 having an opening 28 , a regrown layer 27 including a channel, a gate electrode G, a source electrode S, and a drain electrode D. The regrown layer 27 includes an electron transit layer 22 and an electron supply layer 26 . The GaN-based layered body includes a p-type GaN layer 6 whose end surface is covered by the regrown layer in the opening, and a p-side electrode 11 that is in ohmic contact with the p-type GaN layer is disposed.
1. A semiconductor device comprising:
a GaN-based layered body having an opening;
a regrown layer that includes a channel and is epitaxially grown so as to cover the opening of the GaN-based layered body;
a gate electrode located on the regrown layer in the opening;
a source electrode located on the GaN-based layered body around the opening so as to be in contact with the regrown layer; and
a drain electrode located so that the drain electrode and the source electrode sandwich the channel, the drain electrode being apart from the source electrode in a thickness direction of the GaN-based layered body,
wherein the regrown layer includes an electron transit layer and an electron supply layer, and the channel is a two-dimensional electron gas formed in the electron transit layer at an interface between the electron transit layer and the electron supply layer;
the regrown layer separating the source electrode from the GaN-based layered body, and
the GaN-based layered body includes a p-type GaN-based semiconductor layer whose end surface is covered by the regrown layer on a wall surface of the opening, and a p-side electrode that is in ohmic contact with the p-type GaN-based semiconductor layer is disposed.
2. The semiconductor device according to claim 1 , wherein the p-side electrode is present inside the source electrode when viewed in plan, penetrates so as to extend between the p-type GaN-based semiconductor layer and the source electrode, and is in ohmic contact with the source electrode.
3. The semiconductor device according to claim 1 , wherein an insulating layer is formed on the regrown layer and below the gate electrode.
4. A method for producing a semiconductor device, the method comprising:
a step of forming a GaN-based layered body including a p-type GaN-based semiconductor layer on a predetermined crystal face of GaN;
a step of forming an opening in the GaN-based layered body by etching, the opening penetrating the p-type GaN-based semiconductor layer;
a step of epitaxially growing a regrown layer in the opening of the GaN-based layered body, the regrown layer including an electron transit layer and an electron supply layer;
a step of making a vertical hole that extends from a surface around the opening to the p-type GaN-based semiconductor layer and then forming a conductive portion by filling the vertical hole with a conductive material; and
a step of forming a source electrode so that the source electrode is electrically in contact with the conductive portion and the regrown layer in the opening, the regrown layer separating the source electrode from the GaN-based layered body.