Hetero-junction bipolar transistor and method of manufacturing the same

A hetero-junction bipolar transistor comprising:

• a heat dissipation substrate comprising an insulating material having a thermal conductivity higher than that of InP;
• a first emitter electrode on the heat dissipation substrate;
• a second emitter electrode on the first emitter electrode and having an area smaller than that of the first emitter electrode;
• an emitter layer comprising a first compound semiconductor on the second emitter electrode;
• a base layer comprising a second compound semiconductor on the emitter layer;
• a collector layer comprising a third compound semiconductor on the base layer;
• a collector contact layer comprising a fourth compound semiconductor on the collector layer;
• a collector electrode on the collector contact layer;
• a base electrode configured to be connected to the base layer;
• a protective layer on the heat dissipation substrate covering a side of an element part, the first emitter electrode, and the base electrode the element part comprising the second emitter electrode, the emitter layer, the base layer, the collector layer, the collector contact layer;
• an emitter contact electrode in contact with a top of the first emitter electrode around the element part and penetrating the protective layer;
• an emitter wiring on the protective layer and connected to the emitter contact electrode;
• a heat dissipation structure comprising a metal and having one end in contact with a top of the heat dissipation substrate around the element part and extending through the protective layer;
• a collector wiring on the protective layer in contact with the top of the heat dissipation substrate and the collector electrode;
• a base contact electrode connected to the base electrode and penetrating the protective layer;
• and
• a base wiring on the protective layer and connected to the base contact electrode.

A manufacturing method for manufacturing a hetero-junction bipolar transistor, the method comprising:

• performing crystal growth of an etch stop layer, a collector contact forming layer, a collector forming layer, a base forming layer, and an emitter forming layer in this order, wherein each of the etch stop layer, the collector contact forming layer, the collector forming layer, the base forming layer, and the emitter forming layer comprise a compound semiconductor on a growth substrate comprising InP;
• forming an element part by forming a second emitter electrode on the emitter forming layer, processing the emitter forming layer, the base forming layer, and the collector forming layer to form an emitter layer, a base layer, and a collector layer, and forming a base electrode on the base layer around the emitter layer;
• forming a first structure body comprising a first metal on the growth substrate around the element part;
• filling a periphery of the element part and forming a first protective layer in which one end side of the first structure body and the second emitter electrode are exposed and a surface is flattened;
• forming a first adhesive metal layer on the flattened surface of the first protective layer;
• preparing a heat dissipation substrate comprising an insulating material having higher thermal conductivity than that of InP and in which a second adhesive metal layer is formed on the surface;
• bringing the first adhesive metal layer of the growth substrate and the second adhesive metal layer of the heat dissipation substrate into contact with each other so as to face each other, forming an adhesive metal layer in which the first adhesive metal layer and the second adhesive metal layer are integrated, and laminating the growth substrate and the heat dissipation substrate;
• removing the growth substrate and the etch stop layer, bringing the element part into a state of being formed on the heat dissipation substrate in a state where the second emitter electrode is disposed on a side of the heat dissipation substrate, and exposing the collector contact forming layer;
• forming a collector electrode on the collector contact forming layer;
• forming a collector contact layer by processing the collector contact forming layer and further removing a part of the collector layer and the base layer and forming a contact hole reaching a part of the base electrode;
• forming a first emitter contact electrode comprising a part of an emitter contact electrode and a first heat dissipation structure comprising a second metal and comprising a part of a heat dissipation structure and forming a base contact electrode on the first structure body;
• forming an emitter contact layer by processing the first structure body and forming a second emitter contact electrode connecting to the first emitter contact electrode, forming a second heat dissipation structure comprising a part of the heat dissipation structure and connected to the first heat dissipation structure, forming a first emitter electrode by processing the adhesive metal layer, and forming a third heat dissipation structure connected to the second heat dissipation structure to form the heat dissipation structure comprising the first heat dissipation structure, the second heat dissipation structure, and the third heat dissipation structure;
• forming a second protective layer on the first protective layer to form a protective layer comprising the first protective layer and the second protective layer;
• and
• forming an emitter wiring, a base wiring, and a collector wiring.