Liquid phase epitaxy (LPE) growth mechanisms and the effects of impurities were investigated using a new method. It was demonstrated that the Volmer–Weber mechanism operates on (0 0 1), a K face according to the Hartman–Perdok theory, whereas the Frank–van der Merve mechanism operates on (1 1 0), an F face, and on (1 1 1), an S face. It was also confirmed that tri-valent cations with ionic radii close to Ti 4+ ions transform the character of the (1 1 1) face from an S face to a K face, producing a greatly accelerated growth rate in the c-axis direction, whereas the same impure ions reduce the growth rate on the (1 1 0) face. This difference is well represented in the change of the surface morphologies of the respective faces. The observed morphological changes are interpreted on the assumption that oxygen ions around Ti 4+ ions are destabilized by the adsorption of tri-valent cations, leading to breaking the PBC in the (1 1 1) face.