NdF3 layers were grown on Si(111) substrates at 400, 550, and 700 degreesC by molecular beam epitaxy. The surface morphology observations by atomic force microscopy indicated that the NdF3 layers on Si(111) substrates grew as islands associated with screw dislocations, which coalesced less densely at higher growth temperatures. The layers grown at higher temperatures were more susceptible to formation of microcracks due to larger mismatch of the thermal expansion coefficient. The orientational relationship between NdF3 layers and Si(111) substrates was confirmed to be NdF3(0002) <11-20> \\Si(111) <1-10> by x-ray diffraction measurement. As a function of growth temperature and layer thickness, the crystallinity of resulting layers in terms of full width at half maximum values was investigated. In particular, for NdF3 layers grown at a high temperature of 700 degreesC, lattice relaxation and crystallinity degradation with layer thickening were found. (9) 2001 American Vacuum Society.