An integrated semiconductor circuit includes a substrate having a surface of a first semiconductor material, at least one separating material formed on the surface and defining a through hole, and a guide region formed in the hole. The guide region comprises at least one second semiconductor material. The guide region comprises at least a first region and a second region having a larger cross-section than the first region. The first region contacts the surface of the substrate over a small contact region. Methods of making the integrated semiconductor circuit are also disclosed.