Nitride semiconductor device and method for manufacturing nitride semiconductor device

A nitride semiconductor device having a normally-off characteristic comprising:

• a substrate;
• a nitride buffer layer formed on the substrate;
• a first nitride semiconductor layer formed on the nitride buffer layer;
• a second nitride semiconductor layer formed on the first nitride semiconductor layer and having an Al composition higher than the first nitride semiconductor layer;
• a source electrode and a drain electrode formed on the second nitride semiconductor layer at a distance from each other;
• an insulator protection film layer formed in a region between the source electrode and the drain electrode and having an opening portion for division into a source electrode side and a drain electrode side;
• a gate layer formed covering at least a side surface and a bottom surface of the opening portion;
• a gate electrode formed covering the gate layer, and a water repellent film layer formed in an interface between the insulator protection film layer and the gate electrode,
• the side surface of the opening portion being a surface of the insulator protection film layer, the bottom surface of the opening portion being a surface of the second nitride semiconductor layer,
• the source electrode, the gate layer, and the drain electrode being formed on the same plane on the second nitride semiconductor layer,
• the gate layer being made of a p-type metal oxide semiconductor.

A nitride semiconductor device having a normally-off characteristic comprising:

• a substrate;
• a nitride buffer layer formed on the substrate;
• a first nitride semiconductor layer formed on the nitride buffer layer;
• a second nitride semiconductor layer formed on the first nitride semiconductor layer and having an Al composition higher than the first nitride semiconductor layer;
• a source electrode and a drain electrode formed on the second nitride semiconductor layer at a distance from each other;
• an insulator protection film layer formed in a region between the source electrode and the drain electrode and having an opening portion for division into a source electrode side and a drain electrode side;
• a gate layer formed covering at least a side surface and a bottom surface of the opening portion;
• a gate electrode formed covering the gate layer, and
• a water repellent film layer formed in an interface between the insulator protection film layer and the gate electrode,
• the side surface of the opening portion being a surface of the insulator protection film layer, the bottom surface of the opening portion being a surface of the second nitride semiconductor layer,
• the gate layer formed in the opening portion of the insulator protection film layer being divided via a space for the source electrode and the drain electrode,
• the source electrode, the gate layer, and the drain electrode being formed on the same plane on the second nitride semiconductor layer,
• the gate layer being made of a p-type metal oxide semiconductor.

A method of manufacturing a nitride semiconductor device comprising the steps of:

• forming a nitride buffer layer on a substrate;
• forming a first nitride semiconductor layer on the nitride buffer layer;
• forming a second nitride semiconductor layer on the first nitride semiconductor layer, the second nitride semiconductor layer having an Al composition higher than the first nitride semiconductor layer;
• forming a source electrode and a drain electrode on the second nitride semiconductor layer at a distance from each other;
• forming an insulator protection film layer on the second nitride semiconductor layer including upper portions of the source electrode and the drain electrode;
• forming an opening portion in the insulator protection film layer between the source electrode and the drain electrode;
• forming a gate layer to cover the opening portion and at least a portion of the insulator protection film layer;
• and
• forming a gate electrode on the gate layer, wherein
• in the method of manufacturing the gate layer,
• the opening portion is configured to have a surface of the second nitride semiconductor layer and a surface of the insulator protection film layer, and wherein
• the step of forming the gate layer includes a water repellent film forming step of applying patterning through chemical modification with a water repellent film layer onto the insulator protection film layer except a region to be provided with the gate layer so as to selectively grow the gate layer by using an atomic layer deposition method.

A method of manufacturing a nitride semiconductor device comprising the steps of:

• forming a nitride buffer layer on a substrate;
• forming a first nitride semiconductor layer on the nitride buffer layer;
• forming a second nitride semiconductor layer on the first nitride semiconductor layer, the second nitride semiconductor layer having an Al composition higher than the first nitride semiconductor layer;
• forming an insulator protection film layer on the second nitride semiconductor layer;
• forming an opening portion in the insulator protection film layer, the opening portion having a bottom surface defined as a surface of the second nitride semiconductor layer;
• forming a gate layer to cover the opening portion;
• and
• forming a gate electrode of a p-type metal oxide semiconductor on the gate layer, and removing the insulator protection film layer on both sides of the gate electrode to form a source electrode and a drain electrode at a distance from each other on the second nitride semiconductor layer by a self-alignment method using the gate layer and the gate electrode, wherein
• in the method of manufacturing the gate layer,
• the step of forming the gate layer includes a water repellent film forming step of applying patterning through chemical modification with a water repellent film layer onto the insulator protection film layer except a region to be provided with the gate layer so as to selectively grow the gate layer by using an atomic layer deposition method.