High-quality InAlAs layers lattice matched to InP were successfully grown on (411)A-oriented InP substrates by molecular beam epitaxy (MBE). High-resolution x-ray diffraction and photoluminescence (PL) measurements of InAlAs layers grown on (411)A InP substrates revealed that crystalline quality of the (411)A InAlAs layer strongly depends on the substrate temperature (T-s), and much improved crystalline quality of (411)A InAlAs layer was achieved at a high T-s (570 degrees C). The linewidth of the PL (12 K) peak from the best (411)A InAlAs layer is 10.7 meV which is 16%-29% smaller than those (12.8-15 meV) of InAlAs layers grown on conventional (100)InP substrates by MBE.