PURPOSE: To prevent generation of defects such as cracks and reduce etch pit through reduction of surface roughness of the epitaxial growth layer and reduction of substrate warpage by providing superlattice layers and a compound semiconductor layer grown under a low temperature as the buffer layers be tween the crystal substrate and compound semiconductor layer.
CONSTITUTION: A super lattice layers 3b, 3c and a compound semiconductor layer 4 grown under a low temperature are formed as buffer layers between a crystal substrate 1 and a compound semiconductor layer 2 grown thereon. For example, a GaP layer 3a having almost the same lattice constant as the silicon is formed on the silicon substrate 1 of about 0.05 μm thick and a first superlattice layer 3b equivalent to the GaP/GaAs superlattice after the growth of 5 periods and a second superlattice layer 3c equivalent to the GaAsP/GaAs superlattice after the growth of 5 periods are formed thereon. Thereafter, an ordinary GaAs layer 2 is formed therefore in the thickness of 2 μm or more through the GaAs layer 4 in the thickness of 0.05 μm grown under the tempera ture of about 450°C.
UMENO MASAYOSHI
IMORI TORU
NIPPON MINING CO
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