Using the liquid phase epitaxy technique under supercooling conditions we have grown In0.14Ga0.86As0.13Sb0.87 layers doped with tellurium lattice-matched to (100) n-GaSb. Layers doped with Te were accomplished by incorporating Sb2Te3 pellets into the growth melt in the range from 6.48×10-6M to 4.31×10-4M. Using Raman spectroscopy we characterized the structural quality. Two main bands are observed in the Raman spectra centered at 230 and 245 cm-1 which depend strongly on the molar concentration of Sb2Te3. The assignation of the observed vibrational modes to GaAs-like and to (GaSb+InAs)-like mixture modes is discussed using the random-element isodisplacement (REI) model. The REI model seems to describe the observed behavior of vibrational modes reasonably.