Semiconductor device and fabrication method

A method for fabricating a semiconductor device, the method comprising:

• sequentially forming a first semiconductor layer and a second semiconductor layer on a substrate;
• forming a dielectric layer having an opening after the forming of the second semiconductor layer;
• forming a third semiconductor layer containing a p-type impurity element on the second semiconductor layer exposed from the opening of the dielectric layer;
• and
• forming a gate electrode on the third semiconductor layer.

A semiconductor device comprising:

• a first semiconductor layer formed on a substrate;
• a second semiconductor layer formed on the first semiconductor layer;
• a semiconductor cap layer formed on the second semiconductor layer;
• a third semiconductor layer formed in a first region of the semiconductor cap layer;
• a gate electrode formed on the third semiconductor layer, the third semiconductor layer being formed in the first region of the semiconductor cap layer located beneath the gate electrode;
• and
• a source electrode and a drain electrode formed such that the source electrode and the drain electrode come in contact with the second semiconductor layer or the semiconductor cap layer, wherein
• the semiconductor cap layer and the third semiconductor layer are formed by doping a p-type impurity element to a semiconductor material, and
• the third semiconductor layer is a p-type semiconductor layer.