Heterojunction bipolar transistor

The present disclosure relates to semiconductor structures and, more particularly, to heterojunction bipolar transistors and methods of manufacture. The structure includes: a first semiconductor layer including a device region; a second semiconductor layer under the first semiconductor layer; a layer of conductive material between the first semiconductor layer and the second semiconductor layer; at least one contact extending to and contacting the layer of conductive material; and a device in the device region above the layer of conductive material. 本公开涉及半导体结构，更具体地涉及异质结双极型晶体管及制造方法。该结构包括：第一半导体层，其包括器件区域；第二半导体层，其位于第一半导体层下方；导电材料层，其位于第一半导体层和第二半导体层之间；至少一个接触，其延伸到导电材料层并与导电材料层接触；以及器件，其位于导电材料层上方的器件区域中。