| 摘要 |
<p>PURPOSE:To improve the yield of a void-free crystal of good quality in the pulling up method for preparing a single crystal of Bi4Ge3O12 from a high-viscocity melt, by using a crucible having a height larger than the diameter thereof. CONSTITUTION:A crucible 1 is filled with a raw material melt 2 of Bi4Ge3O12 (BGO) molten by the high-frequency heating to a surface level 3. A seed crystal 4 is then dipped in the melt 2 and pulled up slowly while rotating to give a single crystal 5 of the BGO. When the single crystal 5 is pulled up to reduce the amount of the melt 2 and the depth of the melt 2 reaches a level 6 equal to the diameter of the single crystal 5, voids 7 are formed. In ths state, the forced convection by the rotation of the crystal will not reach the crucible wall in the case of the melt level 6 or below due to the high viscosity of BGO melt. A crucible having a height larger than the diameter thereof is used to reduce the amount of th remaining melt and improve the yield of the single crystal 5.</p> |
