| 摘要 |
<p>A method of controlling a floating zone applied to a crystal manufacturing system based on the FZ method and designed to enable the diameter at the crystallization boundary and the axial length of the floating zone or other similar quantities to desired values, in which a floating zone (20) is imaged with an imaging device (30); geometric quantities of the floating zone is measured from the image thereby obtained; the electric power (P) supplied to an induction heating coil (12) and the speed (VP) at which a raw-material rod (16) is moved relative to the induction heating coil so that the geometric quantities become equal to desired values. The geometric values include one Zi of the axial length of the floating zone, the distance (L) between the induction heating coil and a crystallization boundary (24) and the diameter (Dn) of a melt neck portion located on the side of the crystallization boundary at a predetermined distance from the induction heating coil, and one Di of the diameter (Ds) of the crystallization boundary and the diameter (Dm) of a melt shoulder portion (34) located between the crystallization boundary and the restricted portion at a predetermined distance (hm) from the crystallization boundary. If a desired value of the Zi is Zo, a desired value of the Di is Do and M = (Zi - Zo) (Di - Do), the contribution of control of the relative speed (VP) is smaller when Zi = Zo and Di = Do are not satisfied substantially and M > 0 than it is when Zi = Zo and Di = Do are substantially satisfied (104, 106), and the contribution of control of the electric power (P) is smaller when Zi = Zo and Di = Do are not satisfied substantially and M < 0 than it is when Zi = Zo and Di = Do are satisfied substantially (112, 122).</p> |
