Heterojunction bipolar transistor

A structure comprising:

• a semiconductor substrate;
• a sub-collector region over the semiconductor substrate;
• electrically insulating heat dissipative material under the sub-collector region and extending into the semiconductor substrate;
• a collector region over the sub-collector region;
• an intrinsic base over the collector region;
• an extrinsic base over the intrinsic base;
• and
• an emitter region adjacent to the extrinsic base.

A method comprising:

• forming a sub-collector region comprising a top semiconductor material of a semiconductor substrate and an upper semiconductor material over the top semiconductor material;
• forming an electrically insulating heat dissipative material at junction between the top semiconductor material and the upper semiconductor material of the sub-collector region;
• forming a collector region above the sub-collector region;
• forming an intrinsic base over the collector region;
• forming an extrinsic base over the intrinsic base;
• and
• forming an emitter region adjacent to the extrinsic base.