Wärmeabschirmungselement einer Vorrichtung zum Heraufziehen eines Siliciumeinkristalls

摘要

A heat shielding member is provided in a device pulling up a silicon single crystal rod from a silicon melt stored in a quartz crucible, and equipped with a tube portion which shields radiant heat from the heater surrounding the outer peripheral face of the silicon single crystal rod, a swelling portion provided at the lower portion of the tube portion, and a ring-shape heat accumulating portion provided at the inside of the swelling portion. The heat accumulating portion is a thermal conductivity of 5 W/(m.° C.) or less, its inner peripheral face is a height (H₁) of 10 mm or more and d/2 or less when the diameter of the silicon single crystal rod is referred to as d and the minimum distance (W₁) between the outer peripheral face of the silicon single crystal rod and the inner peripheral face of the heat accumulating portion is formed so as to be 10 mm or more and 0.2 d or less, a vertical distance (H₂) between the upper rim of the outer peripheral face and the lowest portion of the heat accumulating portion is 10 mm or more and d or less, and the minimum distance (W₂) between the inner peripheral face of the quartz crucible and the outer peripheral face of the heat accumulating portion is 20 mm or more and d/4 or less.