The invention relates to a method for fabricating a semiconductor circuit comprising providing a semiconductor substrate; fabricating a first semiconductor device comprising a first semiconductor material on the substrate and forming an insulating layer comprising a cavity structure on the first semiconductor device. The cavity structure comprises at least one growth channel and the growth channel connects a crystalline seed surface of the first semiconductor device with an opening. Further steps include growing via the opening from the seed surface a semiconductor filling structure comprising a second semiconductor material different from the first semiconductor material in the growth channel; forming a semiconductor starting structure for a second semiconductor device from the filling structure; and fabricating a second semiconductor device comprising the starting structure. The invention is notably also directed to corresponding semiconductor circuits.