Oxygen deficiency which is an inherent problem in melt grown YVO4 single crystals was investigated by Micro-Probe Raman Spectroscopy (MPRS). External vibrational modes at 157cm(-1), 162cm(-1) and selected internal vibrational modes at 379cm(-1), 840cm(-1) of full Raman spectra were compared with different YVO4 crystals grown by the Czochralski (CZ) technique both with and without annealing in an O-2 atmosphere as well as by top seeded solution growth technique (TSSG) in directly produced oxygen deficiency-flee form. Special differences of above mentioned frequencies and over 1000cm(-1) were observed in the Raman spectra, which could prove that the growth technologies generated different rates of oxygen deficiency in addition to critical intrinsic segregation effects in YVO4 which significantly determine the crystal quality.