US Patent 9570551 Replacement III-V or germanium nanowires by unilateral confined epitaxial growth

A lateral epitaxial growth process is employed to facilitate the fabrication of a semiconductor structure including a stack of suspended III-V or germanium semiconductor nanowires that are substantially defect free. The lateral epitaxial growth process is unidirectional due to the use of masks to prevent epitaxial growth in both directions, which would create defects when the growth fronts merge. Stacked sacrificial material nanowires are first formed, then after masking and etching process to reveal a semiconductor seed layer, the sacrificial material nanowires are removed, and III-V compound semiconductor or germanium epitaxy is performed to fill the void previously occupied by the sacrificial material nanowires.