The crystallinity of GaAs grown on Si with various intermediate layers by metalorganic chemical vapor deposition and characteristics of Schottky diodes fabricated on the grown GaAs/Si have been studied. The GaAs/Si with an Al0.55Ga0.45P intermediate layer has both good crystallinity, x‐ray full width at half maximum of 188 arc sec, and a smooth surface. The Schottky diode fabricated on the GaAs/Si with an Al0.55Ga0.45P intermediate layer also shows good forward and reverse current‐voltage characteristics with an ideality factor of 1.06, as good as for ann‐type GaAs substrate. However, a relatively large leakage current is observed under reverse and small forward bias. This leakage current is caused by generation and recombination through the centers related to dislocations in the GaAs/Si.