Heterojunction bipolar transistor fully self-aligned to diffusion region with strongly minimized substrate parasitics and selective pre-structured epitaxial base link

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

• providing a semiconductor substrate having a trench isolation, wherein a pad resulting from a manufacturing of the trench isolation is arranged on a surface of the semiconductor substrate;
• providing an isolation layer on the surface of the semiconductor substrate and the pad such that the pad is covered by the isolation layer;
• removing the isolation layer up to the pad such that a surface of the pad is exposed;
• and
• selectively removing the pad to obtain an emitter window.