| 摘要 |
PURPOSE:To produce a single-crystal silicon ingot having uniform properties by controlling the number of revolutions of a seed crystal, the number of revolutions of a crucible, and the speed of pulling up according to the pulling up length of the single-crystal silicon in the stage of pulling up the single-crystal silicon. CONSTITUTION:Polycrystalline Si is put in the quartz crucible 2 in a chamber 1, and is heated to melt by a heater 3. While the crucible 2 is rotated, the seed crystal 6 at the bottom end of a pulling up shaft 5 which is rotated reverse from the crucible 2 is dipped in molten Si 4 and is then pulled up to produce a single crystal. To make the concn. of oxygen uniform over the entire part by decreasing the same in the preceding end part (seed crystal side) of a single-crystal Si ingot and increasing the same in the terminal part, the number of revolutions of the crucible 2 is made small in the initial period and is increased at the end period of pulling up. To make the distribution value of the specific resistance in the section and the distribution value of the concn. of oxygen in the section uniform by decreasing the same in the preceding end part and increasing the same in the terminal part, the number of revolutions of the seed crystal is so controlled as to be increased in the initial period and to be decreased in the end period and the speed of pulling up is so controlled as to be decreased in the initial period and to be increased in the end period. |
