Semiconductor device and method for fabricating the same

A semiconductor device, comprising:

• a semiconductor substrate made of a compound semiconductor material;
• a plurality of hetero-junction bipolar transistor type semiconductor elements, each of which having a collector layer, a base layer, and an emitter layer formed in said semiconductor substrate respectively, said base layers of a plurality of said semiconductor elements being formed like a plurality of base fingers extended independently of each other, each of said base finger layers forming an emitter junction with said emitter layer formed on part of itself and having a first base electrode formed separately from said emitter junction, and said emitter layer having an emitter electrode connected thereto;
• a common base wiring for connecting said first base electrodes of a plurality of said semiconductor elements commonly to each other electrically;
• and
• a common emitter wiring for connecting emitter electrodes of a plurality of said semiconductor elements commonly to each other electrically.

A method for fabricating a hetero-junction bipolar transistor type semiconductor device, comprising the steps of:

• preparing a semiconductor substrate in which a collector layer, a base layer, and an emitter layer are formed sequentially;
• forming a first conductive layer on the main surface of said emitter layer;
• patterning said first conductive layer, thereby forming an emitter electrode and forming a dummy electrode so as to be separated from said emitter electrode;
• removing said emitter layer by using said emitter electrode and said dummy electrode as a mask, thereby exposing part of said base layer;
• and
• forming a second conductive layer serving as a base electrode on a part of said exposed base layer by using said emitter electrode and said dummy electrode as a mask.

A method for fabricating a hetero-junction bipolar transistor type semiconductor device, comprising the steps of:

• preparing a semiconductor substrate in which a collector layer, a base layer, and an emitter layer are formed sequentially;
• removing a part of said emitter layer, thereby exposing a part of said base layer;
• forming a photo-resist mask for exposing a part of said base layer on said base layer from which said emitter layer is removed;
• and
• forming a second conductive layer serving as a base electrode by using said photo-resist mask as a mask.