PURPOSE: To obtain a thin GaAS film having remarkably small carbon mixture amount by incorporating specific amount of Sb in the film to overcome a disadvantage of a MOCVD method.

CONSTITUTION: Sb is contained as 0.05W0.3% of GaSb in a thin GaAS film. The reason why the concentration of the Sb in the GaAS as the GaSb is 0.05W0.3% is because it is desired to set to 0.3% or less to endure a distortion due to lattice misalignment in the thin GaAS film of several μm of thickness while it is desired to contain 0.05% or more to generate an Sb doping effect. For example, an Sb-doped thin GaAS thin film having 0.15% of Sb amount as the GaSb is grown on a 2° OFF semiinsulating GaAS substrate (100) under growing conditions of 0.04cc of SbH2 added by MOCVD method, 640°C of substrate temperature, 5 l/min of H2 gas flow rate, atmospheric pressure in a reaction tube 1.1cc of Ga(CH3)3 flow rate and 12.4cc of AsH3 flow rate.