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 (00 1), a K face according to the Hartman-Perdok theory, whereas the Frank-van der Merve mechanism operates on (110), an F face, and on (1 1 1), an S face. It was also confirmed that tri-valent cations with ionic radii close to Ti4+ 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 (110) 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 Ti4+ ions are destabilized by the adsorption of tri-valent cations. leading to breaking the PBC in the (I 1 1) face.