Structural relation between Si and SiC formed by carbon ion implantation

SiC ion beam synthesis by implantation of C ions into Si is a multiple-step process. In our experiments C ion implantation was performed at TII = RT ... 800 °C to a C concentration in the range of 0.3 to 33.5 at% into Si and SIMOX substrates. SiC phase formation and the related lattice strain were studied by different synchrotron X-ray scattering techniques using ROBL at ESRF Grenoble and by transmission electron microscopy:

1. Low ion fluences result in a Si lattice expansion in the order of 1E-3.
2. Intermediate ion fluences and temperatures generate small SiC pre-cursors with enhanced lattice spacings and reduced strain in the Si lattice.
3. High fluences and temperatures form 3C-SiC crystallites with three types of orientation:

• random-like orientation
• fibre texture with axis parallel to the surface normal with a mean orientation spread of 6°
• high alignment to the Si matrix: SiC<001> || Si<001> and SiC<110> || Si<110> due to a partial coherent growth of SiC in the Si matrix. The orientation spread is in the range from 2° to 5°.

Ion beam synthesis of SiC in Si at elevated temperatures favours the growth of highly oriented crystallites.