Abstract: In a semiconductor crystal growth apparatus, a growth vessel enclosing a substrate is evacuated to an ultrahigh vacuum, and gas molecules containing a component element of a semiconductor which should grow on the substrate is introduced according to a predetermined time sequence into the growth vessel from an external gas source. Infrared radiation from an infrared radiation emitting lamp associated with the growth vessel and controlled by a temperature control unit is directed toward and onto the substrate whose temperature is to be maintained at a predetermined setting. Crystal growth of one molecular layer after another can be achieved by the apparatus with dimensional accuracy of the thickness of a single molecular layer.