Vapor phase InxGa1-xAs photodiodes were fabricated for compositionsx = 0-0.57. p+-layers were made by Zn diffusion using ZnAs2as a Source. Dark currents at half the breakdown voltage forx= 0.15, 0.17, and 0.31 were as low as those fabricated by liquid phase epitaxy. The planar structure is superior to a mesa structure with respect to dark current. Dark currents for various compositions were compared with theoretical estimation. Current multiplications in planar diodes withx = 0.31were about 10 at the junction center and 200-300 at the periphery. Response time to 1.06-µm Nd: YAG mode locked laser pulses was measured to be about 250 ps.