  During the formation of Si nanocrystals (Si NC) in Si$_x$C$_{1-x}$ layers via
solid-phase crystallization, the unintended formation of nanocrystalline SiC
reduces the minority carrier lifetime and therefore the performance of
Si$_x$C$_{1-x}$ as an absorber layer in solar cells. A significant reduction in
the annealing time may suppress the crystallization of the SiC matrix while
maintaining the formation of Si NC. In this study, we investigated the
crystallization of stoichiometric SiC and Si-rich SiC using conventional rapid
thermal annealing (RTA) and nonequilibrium millisecond range flash lamp
annealing (FLA). The investigated Si$_x$C$_{1-x}$ films were prepared by
plasma-enhanced chemical vapor deposition and annealed at temperatures from
700${\deg}$C to 1100${\deg}$C for RTA and at flash energies between 34 J/cm$^2$
and 62 J/cm$^2$ for FLA. GIXRD and FTIR were conducted to investigate hydrogen
effusion, Si and SiC NC growth, and SiC crystallinity. Both the Si content and
the choice of the annealing process affect the crystallization behavior. It is
shown that under certain conditions, FLA can be successfully utilized for the
formation of Si NC in a SiC matrix, which closely resembles Si NC in a SiC
matrix achieved by RTA. The samples must have excess Si, and the flash energy
should not exceed 40 J/cm$^2$ and 47 J/cm$^2$ for Si$_{0.63}$C$_{0.37}$ and
Si$_{0.77}$C$_{0.23}$ samples, respectively. Under these conditions, FLA
succeeds in producing Si NC of a given size in less crystalline SiC than RTA
does. This result is discussed in terms of nucleation and crystal growth using
classical crystallization theory. For FLA and RTA samples, an opposite
relationship between NC size and Si content was observed and attributed either
to the dependence of H effusion on Si content or to the optical absorption
properties of the materials, which also depend on the Si content.
