| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a manufacturing method in which, when a c-axis sapphire single crystal is lifted by the CZ method, bubble clusters are not formed in a shoulder portion and an upper straight trunk portion of the single crystal. <P>SOLUTION: In a method of manufacturing a c-axis sapphire single crystal having a straight trunk portion diameter D, when the enlarged diameter portion crystal diameter is d [mm], the crystal lifting speed is L [mm/h], and the enlarged diameter portion radius increase speed is ϕ<SB POS="POST">r</SB>[mm/h] during formation of the enlarged diameter portion (shoulder portion), while 0.6≤d/D<1.0, the crystal lifting speed and the enlarged diameter portion radius increase speed are adjusted such that ϕ<SB POS="POST">r</SB><7.0 mm/h and L<SP POS="POST">3</SP>×ϕ<SB POS="POST">r</SB>are kept within a range of 55 or below. After the crystal diameter D is reached, a single crystal body having a desired straight trunk length is continuously lifted, thereby obtaining a c-axis oriented sapphire single crystal body. The possibility of bubble clusters being formed in the shoulder portion and the straight trunk portion of the sapphire single crystal body obtained by this manufacturing method is extremely low. The rate of acquiring a sapphire single crystal substrate for LEDs from the sapphire single crystal body can be improved. <P>COPYRIGHT: (C)2013,JPO&INPIT |
