Abstract: An indium phosphide crystal substrate has a diameter of 100-205 mm and a thickness of 300-800 ?m and includes any of a flat portion and a notch portion. In any of a first flat region and a first notch region, when an atomic concentration of sulfur is from 2.0×1018 to 8.0×1018 cm?3, the indium phosphide crystal substrate has an average dislocation density of 10-500 cm?2, and when am atomic concentration of tin is from 1.0×1018 to 4.0×1018 cm?3 or an atomic concentration of iron is from 5.0×1015 to 1.0×1017 cm?3, the indium phosphide crystal substrate has an average dislocation density of 500-5000 cm?2.

Abstract: An indium phosphide single-crystal body has an oxygen concentration of less than 1×1016 atoms·cm?3, and includes a straight body portion having a cylindrical shape, wherein a diameter of the straight body portion is more than or equal to 100 mm and less than or equal to 150 mm or is more than 100 mm and less than or equal to 150 mm. An indium phosphide single-crystal substrate has an oxygen concentration of less than 1×1016 atoms·cm?3, wherein a diameter of the indium phosphide single-crystal substrate is more than or equal to 100 mm and less than or equal to 150 mm or is more than 100 mm and less than or equal to 150 mm.

Abstract: An indium phosphide single-crystal body has an oxygen concentration of less than 1×1016 atoms·cm?3, and includes a straight body portion having a cylindrical shape, wherein a diameter of the straight body portion is more than or equal to 100 mm and less than or equal to 150 mm or is more than 100 mm and less than or equal to 150 mm. An indium phosphide single-crystal substrate has an oxygen concentration of less than 1×1016 atoms·cm?13, wherein a diameter of the indium phosphide single-crystal substrate is more than or equal to 100 mm and less than or equal to 150 mm or is more than 100 mm and less than or equal to 150 mm.

Abstract: A semi-insulating compound semiconductor substrate includes a semi-insulating compound semiconductor, the semi-insulating compound semiconductor substrate being configured such that, on a major plane having a plane orientation of (100), a standard deviation/average value of specific resistance measured at intervals of 0.1 mm along equivalent four directions in a <110> direction from a center of the major plane, and a standard deviation/average value of specific resistance measured at intervals of 0.1 mm along equivalent four directions in a <100> direction from the center of the major plane are each not more than 0.1.

Abstract: An indium phosphide crystal substrate has a diameter of 100-205 mm and a thickness of 300-800 ?m and includes any of a flat portion and a notch portion. In any of a first flat region and a first notch region, when an atomic concentration of sulfur is from 2.0×1018 to 8.0×1018 cm?3, the indium phosphide crystal substrate has an average dislocation density of 10-500 cm?2, and when an atomic concentration of tin is from 1.0×1015 to 4.0×1018 cm?3 or an atomic concentration of iron is from 5.0×1015 to 1.0×1017 cm?3, the indium phosphide crystal substrate has an average dislocation density of 500-5000 cm?2.

Abstract: An indium phosphide single-crystal body has an oxygen concentration of less than 1×1016 atoms·cm?3, and includes a straight body portion having a cylindrical shape, wherein a diameter of the straight body portion is more than or equal to 100 mm and less than or equal to 150 mm or is more than 100 mm and less than or equal to 150 mm. An indium phosphide single-crystal substrate has an oxygen concentration of less than 1×1016 atoms·cm?13, wherein a diameter of the indium phosphide single-crystal substrate is more than or equal to 100 mm and less than or equal to 150 mm or is more than 100 mm and less than or equal to 150 mm.

Abstract: A semi-insulating compound semiconductor substrate includes a semi-insulating compound semiconductor, the semi-insulating compound semiconductor substrate being configured such that, on a major plane having a plane orientation of (100), a standard deviation/average value of specific resistance measured at intervals of 0.1 mm along equivalent four directions in a <110> direction from a center of the major plane, and a standard deviation/average value of specific resistance measured at intervals of 0.1 mm along equivalent four directions in a <100> direction from the center of the major plane are each not more than 0.1.