Nitride semiconductor device and method for manufacturing same

A method of manufacturing a nitride semiconductor device comprising a source electrode and a drain electrode formed on semiconductor stacked layers comprising a nitride semiconductor, and a gate electrode formed between the source electrode and the drain electrode, the method comprising:

• forming the semiconductor stacked layers comprising a buffer layer, a carrier running layer formed on the buffer layer, and a barrier layer formed on the carrier running layer, on a substrate;
• forming a gate insulating film on the semiconductor stacked layers;
• forming a gate metal layer comprised in the gate electrode selectively on the gate insulating film;
• forming a surface passivation film on the gate insulating film and the gate metal layer;
• removing the surface passivation film on the gate metal layer, and forming a barrier metal layer on the surface passivation film and on the gate metal layer;
• removing the barrier metal layer in regions, the source electrode and the drain electrode are formed in the regions, after forming the barrier metal layer on the surface passivation film and on the gate metal layer;
• removing the surface passivation film in the regions and further removing a part of a surface of the barrier layer by using the barrier metal layer as a mask;
• forming a contact layer on the barrier metal layer and on the part of the surface of the barrier layer and further forming a metal layer comprising Al on the contact layer after removing the part of the surface of the barrier layer;
• forming a mask opening between a region in which the gate electrode is disposed and a region in which the source electrode is disposed and between the region in which the gate electrode is disposed and a region in which the drain electrode is disposed, on the metal layer comprising Al;
• and
• removing the contact layer and the metal layer comprising Al between the region in which the gate electrode is disposed and the region in which the source electrode is disposed and between the region in which the gate electrode is disposed and the region in which the drain electrode is disposed by using the mask.