A two-dimensional carrier is generated in the vicinity of an interface
that is a hetero interface between a semiconductor layer and a
semiconductor layer. Two concave portions are formed so as to extend from
a primary surface as far as the interface. An electrode that is made of
metal and provides a Schottky junction with the semiconductor layers is
formed on a bottom surface and a side surface of the concave portion. An
electrode that is made from metal and provides a low resistance contact
with the semiconductor layers and is also in low resistance contact
therewith is formed on the bottom surface and side surface of the concave
portion. As a result, a semiconductor device is provided in which contact
resistance between the electrodes and the semiconductor layers is reduced
and high frequency characteristics are improved.