Patent DE-102009016133-A1 (DE)
Title: Producing aluminum nitride volume single crystal, comprises disposing monocrystalline aluminum nitride seed crystal in crystal growth region of crucible arrangement, and producing aluminum nitride growth gas phase in crystal growth region
Inventor: BARZ RALPH-UWE
IPC: C30B23/02
Filed: 2009-04-03
Abstract: The process comprises disposing a monocrystalline aluminum nitride seed crystal (15) in a crystal growth region (4) of a crucible arrangement (3) with a center central longitudinal axis, producing an aluminum nitride growth gas phase in the crystal growth region during a growth phase, feeding the aluminum nitride growth gas phase partially from an aluminum nitride source material present in a storage region (5) of the crucible arrangement, and growing the aluminum nitride volume single crystal onto the aluminum nitride seed crystal in a growth direction (17). The process comprises disposing a monocrystalline aluminum nitride seed crystal (15) in a crystal growth region (4) of a crucible arrangement (3) with a center central longitudinal axis, producing an aluminum nitride growth gas phase in the crystal growth region during a growth phase, feeding the aluminum nitride growth gas phase partially from an aluminum nitride source material present in a storage region (5) of the crucible arrangement, growing the aluminum nitride volume single crystal onto the aluminum nitride seed crystal in a growth direction (17) oriented parallel to the central longitudinal axis by deposition from the aluminum nitride growth gas phase, reducing an oxygen portion of the aluminum nitride source material during a cleaning phase, and keeping the aluminum nitride source material in an oxygen-free atmosphere after concluding the cleaning phase and during the entire growth phase. An incongruent evaporation of oxygen-containing components from the aluminum nitride source material is induced during the cleaning phase. The crucible arrangement comprises a deposition chamber, in which the oxygen-containing components evaporated from the aluminum nitride source material are deposited during the cleaning phase. The deposition chamber is separated from the storage region and the crystal growth region after concluding the cleaning phase to suppress a gas exchange between the deposition chamber and the crystal growth region. The storage region is arranged between the crystal growth region and the deposition chamber viewed in the direction of the central longitudinal axis. A deposition temperature is adjusted in the deposition chamber during the cleaning phase and the growth phase and is 5% lower than a storage temperature adjusted in the storage region. During the cleaning phase, a crystal temperature is adjusted in the aluminum nitride seed crystal and is greater than the storage temperature adjusted in the storage region. During the growth phase, a crystal temperature is adjusted in the growth boundary surface of the growing-up silicon carbide volume single crystal and is 1% lower than the storage temperature adjusted in the storage region. An additional process gas such as nitrogen is supplied to the crucible arrangement and a process gas partial pressure of the process gas during the cleaning phase is adjusted than during the growth phase and is adjusted to a value of 2x 10 2>Pa to 10 5>Pa. The growth phase is carried out in direct connection to the cleaning phase. The storage region is formed as an inner crucible insert, where the aluminum nitride source material required for the growth phase is completely introduced into the inner crucible insert before beginning the cleaning phase. An independent claim is included for a single crystal aluminum nitride substrate.