VAPOR PHASE EPITAXY

摘要

PURPOSE:To form a thin good-quality semiconductor film by vapor phase epitaxy on a semiconductor layer having a diffraction grating while satisfactorily maintaining the periodic ruggedness of the diffraction grating by preheating the semiconductor layer in two stages under specific conditions, then subjecting the same to crystal growth. CONSTITUTION:A 1st preheating gas (e.g.; PH3+H2) is admitted into a preheating region A and a 2nd preheating gas (e.g.; PH3+AsH3+H2) is admitted into a preheating region B. The semiconductor layer 1 formed with the diffraction grating having the periodic ruggedness is then moved to the preheating region A and is preheated up to the temp. at which the diffraction grating is nt annihilated and the component of the 2nd preheating gas does not stick onto the semiconductor layer 1. The semiconductor layer 1 is thereafter moved to the preheating region B and is preheated up to the growth temp. of the thin semiconductor film to be grown on the semiconductor layer 1. The semiconductor layer 1 is next moved into a growth chamber 8 into which the gas of the thin semiconductor film to be subjected to crystal growth is injected. The thin semiconductor film 3 is thus formed on the diffraction grating 1.