Abstract: An object is to provide a compound semiconductor substrate and a surface-treatment method thereof, in which, even after the treated substrate is stored for a long period of time, resistance-value defects do not occur. Even when the compound semiconductor substrate is stored for a long period of time and an epitaxial film is then formed thereon, electrical-characteristic defects do not occur. The semiconductor substrate according to the present invention is a compound semiconductor substrate at least one major surface of which is mirror-polished, the mirror-polished surface being covered with an organic substance containing hydrogen (H), carbon (C), and oxygen (O) and alternatively a compound semiconductor substrate at least one major surface of which is mirror-finished, wherein a silicon (Si) peak concentration at an interface between an epitaxial film grown at a growth temperature of 550° C. and the compound semiconductor substrate is 2×1017 cm?3 or less.

Abstract: An object is to provide a compound semiconductor substrate and a surface-treatment method thereof, in which, even after the treated substrate is stored for a long period of time, resistance-value defects do not occur. Even when the compound semiconductor substrate is stored for a long period of time and an epitaxial film is then formed thereon, electrical-characteristic defects do not occur. The semiconductor substrate according to the present invention is a compound semiconductor substrate at least one major surface of which is mirror-polished, the mirror-polished surface being covered with an organic substance containing hydrogen (H), carbon (C), and oxygen (O) and alternatively a compound semiconductor substrate at least one major surface of which is mirror-finished, wherein a silicon (Si) peak concentration at an interface between an epitaxial film grown at a growth temperature of 550° C. and the compound semiconductor substrate is 2×1017 cm?3 or less.

Abstract: Affords AlxGa(1-x)As (0?x?1) substrates epitaxial wafers for infrared LEDs, infrared LEDs, methods of manufacturing AlxGa(1-x)As substrates, methods of manufacturing epitaxial wafers for infrared LEDs, and methods of manufacturing infrared LEDs, whereby a high level of transmissivity is maintained, and through which, in the fabrication of semiconductor devices, the devices prove to have superior light output characteristics. An AlxGa(1-x)As substrate (10a) as disclosed is an AlxGa(1-x)As substrate (10a) furnished with an AlxGa(1-x)As layer (11) having a major surface (11a) and, on the reverse side from the major surface (11a), a rear face (11b), and is characterized in that in the AlxGa(1-x)As layer (11), the amount fraction x of Al in the rear face (11b) is greater the amount fraction x of Al in the major surface (11a). The AlxGa(1-x)As substrate (10a) may additionally be provided with a GaAs substrate (13), contacting the rear face (11b) of the AlxGa(1-x)As layer (11).

Abstract: The present invention makes available AlxGa(1-x)As (0?x?1) substrates, epitaxial wafers for infrared LEDs, infrared LEDs, methods of manufacturing AlxGa(1-x)As substrates, methods of manufacturing epitaxial wafers for infrared LEDs, and methods of manufacturing infrared LEDs, whereby a high level of transmissivity is maintained, and through which, in the fabrication of semiconductor devices, the devices prove to have superior characteristics. An AlxGa(1-x)As substrate (10a) of the present invention is an AlxGa(1-x)As substrate (10a) furnished with an AlxGa(1-x)As layer (11) having a major surface (11a) and, on the reverse side from the major surface (11a), a rear face (11b), and is characterized in that in the AlxGa(1-x)As layer (11), the amount fraction x of Al in the rear face (11b) is greater than the amount fraction x of Al in the major surface (11a).

Abstract: Affords AlxGa(1-x)As (0?x?1) substrates, epitaxial wafers for infrared LEDs, infrared LEDs, methods of manufacturing AlxGa(1-x)As substrates, methods of manufacturing epitaxial wafers for infrared LEDs, and methods of manufacturing infrared LEDs, whereby a high level of transmissivity is maintained, and through which, in the fabrication of semiconductor devices, the devices prove to have superior characteristics. An AlxGa(1-x)As substrate (10a) of the present invention is an AlxGa(1-x)As substrate (10a) furnished with an AlxGa(1-x)As layer (11) having a major surface (11a) and, on the reverse side from the major surface (11a), a rear face (11b), and is characterized in that in the AlxGa(1-x)As layer (11), the amount fraction x of Al in the rear face (11b) is greater than the amount fraction x of Al in the major surface (11a). In addition, the AlxGa(1-x)As substrate (10a) is further furnished with a GaAs substrate (13), contacting the rear face (11b) of the AlxGa(1-x)As layer (11).