Single‐crystal films of have been grown on semi‐insulating substrates by the decomposition of triethylindium and arsine over a temperature range of 550°–650°C. The growth is mass‐transport limited above 575°C and kinetically controlled below 575°C. Films of more than 0.5 µm have specular surfaces. Optimum growth conditions occur at a substrate temperature of 600°C, a flow of 2 mliters/min arsine (pure), and 2.5 liters/min hydrogen flow through the TEI bubbler.