Abstract: A semiconductor device includes: a substrate; and an n-type layer including a nitride semiconductor formed on the surface of the substrate. In the n-type layer, the concentration of donor impurities (excluding O) is 1×1015 cm?3 or more and 1×1020 cm?3 or less, the concentration of C impurities is 1×1016 cm?3 or less, the concentration of O impurities is 1×1016 cm?3 or less, the concentration of Ca impurities is 1×1016 cm?3 or less, and the sum total of the concentrations of the C impurities, the O impurities, and the Ca impurities is lower than the concentration of the donor impurities. Such a semiconductor device can be fabricated by using a halogen-free vapor phase epitaxy (HF-VPE) device.

Abstract: An apparatus for manufacturing compound single crystal includes a crystal growth section to hold a seed crystal, a gas supply section to supply a metal-contained gas and a reactant gas toward the seed crystal, and a heating section to heat the seed crystal and a metal source. The gas supply section includes a crucible holding the metal source, a carrier gas supply unit, and a reactant gas supply unit. A porous baffle plate is provided in an opening of the crucible. The porous baffle plate satisfies a relationship of 80%?(1?VH/VB)×100<100% and a relationship of 0.0003<a2/L<1.1. VB is an apparent volume of the porous baffle plate, VH is a total volume of the through-holes contained in the porous baffle plate, “a” is a diameter of the through-hole, and L is a length of the through-hole.

Abstract: A semiconductor device includes: a substrate; and an n-type layer including a nitride semiconductor formed on the surface of the substrate. In the n-type layer, the concentration of donor impurities (excluding O) is 1×1015 cm?3 or more and 1×1020 cm?3 or less, the concentration of C impurities is 1×1016 cm?3 or less, the concentration of O impurities is 1×1016 cm?3 or less, the concentration of Ca impurities is 1×1016 cm?3 or less, and the sum total of the concentrations of the C impurities, the O impurities, and the Ca impurities is lower than the concentration of the donor impurities. Such a semiconductor device can be fabricated by using a halogen-free vapor phase epitaxy (HF-VPE) device.

Abstract: In a gallium nitride crystal, a nanovoid density in the crystal is less than 1×105 [cm?2]. A crystal growth apparatus is an apparatus for manufacturing a gallium nitride crystal, wherein a member having a B concentration of less than 1 ppm at least at a surface part is used as a member used at a part where a temperature is 500° C. or higher (high-temperature member) among members exposed to a crystal growth space. When such a crystal growth apparatus is used, a gallium nitride crystal wherein a nanovoid density in the crystal is less than 1×105 [cm?2] is obtained.

Abstract: An apparatus for manufacturing compound single crystal includes a crystal growth section to hold a seed crystal, a gas supply section to supply a metal-contained gas and a reactant gas toward the seed crystal, and a heating section to heat the seed crystal and a metal source. The gas supply section includes a crucible holding the metal source, a carrier gas supply unit, and a reactant gas supply unit. A porous baffle plate is provided in an opening of the crucible. The porous baffle plate satisfies a relationship of 80%?(1?VH/VB)×100<100% and a relationship of 0.0003<a2/L<1.1. VB is an apparent volume of the porous baffle plate, VH is a total volume of the through-holes contained in the porous baffle plate, “a” is a diameter of the through-hole, and L is a length of the through-hole.

Abstract: In a gallium nitride crystal, a nanovoid density in the crystal is less than 1×105 [cm?2]. A crystal growth apparatus is an apparatus for manufacturing a gallium nitride crystal, wherein a member having a B concentration of less than 1 ppm at least at a surface part is used as a member used at a part where a temperature is 500° C. or higher (high-temperature member) among members exposed to a crystal growth space. When such a crystal growth apparatus is used, a gallium nitride crystal wherein a nanovoid density in the crystal is less than 1×105 [cm?2] is obtained.