Substitutional carbon incorporation in epitaxial Si1−yCy alloys on Si(001) grown by molecular beam epitaxy

Abstract

We show that C incorporation kinetics depend significantly on the carbon concentration. The carbon substitutionality (fraction of substitutional incorporated carbon atoms) is strongly influenced by the growth conditions, such as growth temperature and Si growth rate. In addition, reduction in the growth temperature and increase of the growth rate can both increase the substitutional carbon fraction. This behavior is well described by a kinetic model, with the energy barrier and preexponential frequency factor decreasing with increasing carbon concentration. Very low carbon concentrations (in the dopant range) can be predominantly incorporated substitutionally, independent of the growth temperature. At higher C concentrations (in the percentage range), the substitutional carbon fraction is shifted to lower values. We predict the existence of an upper limit for substitutional C incorporation, with its value depending on the specific growth conditions.

Formation of compressively strained Si/Si1−xCx/Si(100) heterostructures using gas-source molecular beam epitaxy

“…In addition, fluctuations and defects hamper the propagation of dislocations which is also a cause of the inhomogeneity. Regarding the carbonrelated defects, it should be noted that substrate temperature also affects the substitutional to interstitial carbon concentration ratio [12,17] which possibly affects the formation of defects. For samples B and C, the top Si layers are distinguishable in Fig.…”

“…The separation between the partial dislocations depends also on the substrate temperature on which magnitude of the friction stress depends [37,38]. In addition, the substrate temperature affects the strain relaxation process via precipitation of carbon related complexes or b-SiC nanocrystals [17,39,40]. Fig.…”

“…Methods to grow Si 1 À x C x alloys using molecular beam epitaxy (MBE)-based techniques [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], chemical vapor deposition (CVD) [11,[24][25][26][27][28][29][30], and solid phase epitaxy (SPE) [27,31,32] have been extensively studied. However, most of the previous studies were focused on pseudomorphic growths on Si substrate, and there have been only a limited number of investigations on the strain relaxation process during the heteroepitaxial growths of Si 1 À x C x crystalline films [15,22,23].…”

Chemical vapor deposition of Si:C and Si:C:P films—Evaluation of material quality as a function of C content, carrier gas and doping

“…A more likely explanation is the formation of non-stoichiometric Si-C interstitial complexes (which are different from stoichiometric SiC precipitates having a crystalline structure) or C clusters during the growth, acting as defect nucleating centers [17,28]. The formation of non-stoichiometric interstitial Si-C is also supported by the studies of Osten et al [17]. An increase in C concentration reduces the energy barrier to form many Si-C complexes in the lattice.…”

“…A couple of reports pertaining to the use of disilane to grow Si:C layers (in both gas-source Molecular Beam Epitaxy (MBE) as well as Chemical Vapor Deposition (CVD)), are already available [12][13][14][15][16][17][18][19]. Recently, Hartmann et al [19] have demonstrated a selective process for Si:C and Si:C:P deposition using disilane.…”