Alkaline earth fluorides are suitable materials as substrates for the epitaxial growth of several semiconductors, and the (111)surface of cleaved CaF@sub2@ or BaF@sub2@ and (Ca,Ba)F@sub2@ buffer layers on (111)Si have mainly been used. The crystalline quality of epitaxial layers are influenced by the surface morphology and structure of fluoride substrates and it has been known that bombardment of energetic electrons or ultra-violet irradiation makes the surface structure of fluorides change and improve the quality of epitaxial layers on them. In this study, wet chemical treatments were applied to fluoride substrates and their effectiveness was evaluated in improving the surface morphology by atomic force microscopy(AFM) and reflection high energy electron diffraction(RHEED). The polished (111)CaF@sub2@ and BaF@sub2@ substrates with optical flatness were chemically treated at room temperature by using diluted solutions of HF,HCl, and NH@sub4@Cl for the different concentrations and treatment times . The morphological changes of substrates by treatment with different solutions were compared in detail. The best results were obtained for the CaF@sub2@ treated with 16.3%HF for 15 minutes and for the BaF@sub2@ with 0.3%HCl for 35 seconds. Under this condition, the surface roughness(rms) of both substrates could be obtained to be within a few nanometers, which provides a capability for epitaxial growth of high quality layers . Evaluations with RHEED would be also discussed.