| 摘要 |
1,229,508. Magnesium-aluminium spinel. SIEMENS A.G. 19 June, 1969 [20 June, 1968], No. 30972/69. Heading C1A. A magnesium-aluminium spinel monocrystal having a molar ratio of magnesium oxide to aluminium oxide of 1: 25 or less, is produced by the crucible drawing (Czochralski) process. The crystal is produced by drawing a melt of the required composition from a crucible using a seed crystal. The seed crystal may be a magnesium-aluminium spinel monocrystal manufactured by the Verneuil process and having a different magnesium oxide to aluminium oxide ratio from that to be drawn, preferably being greater in aluminium content. A semi-conductor material, e.g. silicon, is then epitaxially deposited on the substrate spinel in a suitable direction, e.g. the (001) direction. The substrate is preferably in the form of plates mechanically separated from the monocrystal produced. |
