Nitride semiconductor device and method for manufacturing same

A method for manufacturing a nitride semiconductor device comprising:

• a step of forming a first nitride semiconductor layer that constitutes an electron transit layer, a second nitride semiconductor layer that constitutes an electron supply layer, and a semiconductor gate layer material film that includes an acceptor type impurity in this order on a substrate;
• a step of forming an electrode film that is a material film for a gate electrode and a hole-pulling-out electrode on the semiconductor gate layer material film;
• a step of forming a semiconductor gate layer having a ridge portion that has a ridge shape and an extension portion that extends from the ridge portion and an electrode film formed on the semiconductor gate layer by means of patterning achieved by etching the electrode film and the semiconductor gate layer material film;
• a step of forming a first dielectric film so as to cover exposed surfaces of the electrode film, of the semiconductor gate layer, and of the second nitride semiconductor layer, and hereafter forming a source contact hole and a drain contact hole that penetrate through the first dielectric film in a thickness direction at mutually-facing positions between which the ridge portion is interposed in the first dielectric film;
• a step of forming a source electrode and a drain electrode that penetrate through the source contact hole and the drain contact hole and that come into contact with the second nitride semiconductor layer;
• and
• a step of, in the extension portion, forming a first annular opening portion having an annular shape in a plan view in the first dielectric film and forming a second annular opening portion having an annular shape in a plan view that communicates with the first annular opening portion in the electrode film, and hence forming the hole-pulling-out electrode that is constituted of the electrode film disposed inside the second annular opening portion and that comes into contact with the extension portion and the gate electrode that is constituted of the electrode film disposed outside the second annular opening portion.

A method for manufacturing a nitride semiconductor device comprising:

• a step of forming a first nitride semiconductor layer that constitutes an electron transit layer, a second nitride semiconductor layer that constitutes an electron supply layer, and a semiconductor gate layer material film that includes an acceptor type impurity in this order on a substrate;
• a step of forming a gate electrode film that is a material film for a gate electrode on the semiconductor gate layer material film;
• a step of forming a semiconductor gate layer having a ridge portion that has a ridge shape and an extension portion that extends from the ridge portion and a gate electrode film formed on the semiconductor gate layer by means of patterning achieved by etching the gate electrode film and the semiconductor gate layer material film;
• a step of forming a first dielectric film so as to cover exposed surfaces of the gate electrode film, of the semiconductor gate layer, and of the second nitride semiconductor layer, and hereafter forming a source contact hole and a drain contact hole that penetrate through the first dielectric film in a thickness direction at mutually-facing positions between which the ridge portion is interposed in the first dielectric film;
• a step of forming a source electrode and a drain electrode that penetrate through the source contact hole and the drain contact hole and that come into contact with the second nitride semiconductor layer;
• a step of, in the extension portion, forming a first opening portion that penetrates through the first dielectric film in a thickness direction and forming a second opening portion that communicates with the first opening portion in the gate electrode film, and hence forming a gate electrode;
• a step of forming a second dielectric film with which a bottom surface of the second opening portion is covered;
• a step of forming a third opening portion that penetrates through the second dielectric film in the thickness direction in the second dielectric film;
• and
• a hole-pulling-out electrode forming step of forming a hole-pulling-out electrode that covers the third opening portion and that comes into contact with the extension portion.