Methods for forming a germanium island using selective epitaxial growth and a sacrificial filling layer

A semiconductor device, comprising:

• a substrate;
• one or more semiconductor layers defining one or more regions that are not covered by the one or more semiconductor layers over the substrate, the one or more semiconductor layers including silicon;
• one or more semiconductor structures located over the one or more regions that are not covered by the one or more semiconductor layers, the one or more semiconductor structures including germanium, a respective semiconductor structure of the one or more semiconductor structures including a first portion located adjacent to the one or more semiconductor layers and a second portion located away from the one or more semiconductor layers, the first portion of the respective semiconductor structure having a height that is less than a height of a portion of the one or more semiconductor layers located adjacent to the first portion of the respective semiconductor structure, the second portion of the respective semiconductor structure having a height that is equal to, or greater than, the height of the portion of the one or more semiconductor layers located adjacent to the first portion of the respective semiconductor structure;
• and
• one or more filling layers located over at least the first portion of the respective semiconductor structure.

A semiconductor device, comprising:

• a substrate;
• one or more first semiconductor structures located over the substrate, a respective first semiconductor structure of the one or more first semiconductor structures having a substantially flat top surface, a substantially vertical side surface, and a diagonal surface extending from the top surface to the side surface, the diagonal surface being non-parallel and non-perpendicular to the top surface and non-parallel and non-perpendicular to the side surface;
• and
• one or more second semiconductor structures, a respective second semiconductor structure of the one or more second semiconductor structures being located on the diagonal surface of a corresponding first semiconductor structure of the one or more first semiconductor structures, the respective second semiconductor structure having a side surface aligned with the side surface of the corresponding first semiconductor structure and a top surface aligned with the top surface of the corresponding first semiconductor structure.