a compound - semiconductor single - crystal - manufacturing apparatus comprises a crucible for holding a molten raw material of gaas and a liquid capsule element of b 2 o 3 , a crucible holder , a heat element concentrically surrounding the crucible , and a heat - shielding unit surrounding the heat element , for use in manufacturing a gaas single crystal by progressively pulling it up from the raw molten material held in the crucible by the liquid encapsulated czochralski process . the heat - shielding unit and crucible holder are formed by molding a sintered aluminum nitride element .