A study has been made on samples of disperse vanadium dioxide (VO2) in a matrix (M = 1500) of polyethylene glycol (PEG) doped with a quaternary ammonium salt (QAS), namely, tetraethylammonium bromide. It has been established that under the influence of the dopant, the heating of a sample up to the temperature of the metal-semiconductor phase transition (MSPT) results in a phase inhomogeneity of the sample. One portion of the disperse VO2 particles passes to the metallic state, while others retain its semiconducting state. The possible cause for the observed phenomenon is the emergence of strong local electric fields between the QAS cations and the VO2 surface. In the region of phase heterogeneity, the MSPT temperature for the semiconducting phase is shifted into a higher temperature interval.