Effects of InP substrate orientation on InxGa1−xAs vapor‐phase epitaxial growth are studied. The fractional compositionxof the grown layer on (100) substrate is smaller than for (111)Bat identical growth temperatures and gas flow rates. The In contentxdecreases with increasing temperature. Growth rate, carrier concentration, and carrier mobility depend on substrate orientation. Growth on (100) substrates at temperatures above 710°C is suitable for obtaining smooth surface layers with low carrier concentration and high mobility.