Photoelectron spectroscopy is often used to characterize the composition and bonding in high dielectric constant materials being developed for the next generation of integrated circuits. However, the peak positions vary continuously as a function of composition and thickness for binary oxides. Thus we have studied the core-level photoemission spectra of hafnium silicates and zirconium silicates, sputter deposited on silicon, as a function of oxide thickness. The metal peak shifts by as much as 1 eV to higher energy as the silicate component is increased. The Si 2p peak also shifts to greater binding energy as silicate component is increased. For pure metal oxide, the O 1s shows two components corresponding to the hydroxide and oxide at higher and lower binding energies respectively. As the silicate component is increased a new component appears at even higher binding energy. In addition to all of these peak shifts, for a given composition, a thin layer (less than 10 nm) has lower binding energies than seen for a corresponding thick film. All of these shifts in metal core-level, Si 2p, and O 1s can be related to two phenomena. The first is the relative electron donation of the metal and Si. Since the metal easily donates its valence electrons to oxygen, the O 1s peak is found at lower binding energies. As the Si component is increased, less electron density is donated to the oxygen, shifting the O 1s to greater binding energies. The oxygen then withdraws slightly more electron density from the metal, shifting its core levels to high binding energy. This reasoning can be used to explain all of the peak shifts seen for a given thickness. Thin films have lower binding energy because electrons near the Fermi energy help screen the positively-charged photoemission final state. This effect has also been seen for thin silicon dioxide films grown on silicon.