Ion beam modification of Si/SiC/Si layer systems

Buried, homogeneous silicon carbide (SiC) layers were formed in (100) and (111) silicon by ion beam synthesis (IBS). In order to study the ion beam induced epitaxial crystallization (IBIEC) of buried SiC layers, the carbide layers were amorphized by irradiation with 2 MeV Si2+ ions at 300 K, followed by solid-phase epitaxial regrowth of surrounding amorphized silicon layers. IBIEC experiments were performed at 320° and 600 °C using a 800 keV Si+ beam. It is shown by transmission electron microscopy and electron diffraction that IBIEC works well on buried SiC layers and results in epitaxial recrystallization at considerably lower target temperatures than necessary for thermal annealing. The IBIEC process starts from both SiC/Si interfaces and may be accompanied by heterogeneous nucleation of poly-SiC as well as interfacial layer-by-layer amorphization, depending on irradiation conditions. The structure of the recrystallized regions in dependence of dose, dose rate, temperature and crystal orientation is described in detail.