Spontaneous Nanopatterning and Strain Relaxation in SiGe Layers Grown by Oxidative Solid‐Phase Epitaxy

The wafer‐scale monolithic integration of III‐V materials on Si would lead to revolutionary optoelectronic hardware for data, computing, and other applications. However, heteroepitaxy of III‐Vs on Si requires overcoming the large lattice and thermal mismatches between the materials and reducing threading dislocation densities. In this work, we explore the oxidative solid‐phase epitaxy (SPE) of Ge + ‐implanted Si(111) to form ultra‐thin strain‐relieving SiGe metamorphic buffer layers for heteroepitaxy on Si. The SPE process is shown to result in a nanopatterning of the Ge concentration variation across the sample surface, visible by scanning and transmission electron microscopy (SEM and TEM). The concentration patterning is the result of a hexagonal network of Shockley partial dislocations at the SiGe/Si interface. Analyzing the pattern spacing observed by SEM is demonstrated as an easy, non‐destructive method for obtaining the local strain state of SiGe layers. This work is important for engineering ultra‐thin SiGe metamorphic buffer layers for III‐V optoelectronics heteroepitaxy on the silicon platform.