Patent ID: 6053974
Filing Date: 2000-04-25
Classification: C30B,Y10S,Y10T

Abstract:
A heat shield for use in a crystal puller around a monocrystalline ingot grown out of a crucible in the crystal puller filled with molten semiconductor source material, the heat shield comprising a reflector having a central opening sized and shaped for surrounding the ingot as the ingot is grown to reduce heat transfer from the crucible, the reflector being adapted to be supported in the crystal puller between said molten material and a camera aimed toward at three separate points on a meniscus formed between the ingot and an upper surface of the molten material, the reflector having at least three passages extending through the reflector, each of said passages being located along an imaginary line extending between the camera and one of said points on the meniscus thereby to permit the camera to view the points so the positions of the points can be determined by the camera for calculating the diameter of the ingot while minimizing heat loss through the passages.