| 摘要 |
Crystals are formed by exposing a semiconductor material melt (16) to an impurity soluble in the semiconductor material and partially pptd. in the material after solidification, and forming a single crystal (20) with embedded impurity from part of the melt (16), the initially formed part of the single crystal having a lower impurity concn. than final part of the single crystal. Formation involves forming rod (20), cutting the rod into wafers, and simultaneously forming parts in the wafers and pptg. part of the impurity of the wafers. Pref. the semiconductor material is Ge or esp. Si and the impurity is N, C or esp. O. The wafers, obtd. from the single crystal, are pref. heated uniformly to a temp. which promotes nucleation of the impurity for the same time. ADVANTAGE - The impurity concn. along the crystal is inversely related to the duration of exposure of each portion of the growing crystal to temps. which promote nucleation of pptes. to ppte. uniform crystal concn. along length. |
