| 摘要 |
FIELD: electricity. ^ SUBSTANCE: crucible for growth of volume single crystal of aluminium nitride includes graphite container 1 with cover 2 and seed 3. Inner surface of container 1 is lined with a layer of polycrystal source - pressed aluminium nitride 4 arranged in the form of ball segment comprising annular 5 external 6 and internal 7 segment surfaces. Besides centres of rotation of inner 7 and outer 6 segment surfaces O and O1 are located over each other and lie on a common axis of surfaces rotation, and annular surface 5 coincides with upper plane 8 of graphite container. Moreover, between outer surface of polycrystal ball segment and inner surface of graphite container there is a gasket 9 made of tantalum installed as coupled with these surfaces, and inner surface of cover 2 is equipped with a gasket 10 of tantalum foil coupled with it. Shape of polycrystal source is selected in the form of ball segment due to certain considerations. First of all, multiple points making inner surface of ball segment is equidistant from surface of seed, which provides a positive impact at evenness of grown crystal structure. Second, ball segment closes all inner surface of container, preventing mixing of graphite particles, from which container is made, with pairs of source components, and annular surface is located at the level of upper cut in container. Third, due to arrangement of outer and inner surfaces over each other, thickness of ball segment wall at the level of upper container cut is less than thickness of ball segment bottom. This condition is necessary to level temperature gradient and even heating of source, taking into account the fact that temperature at lower levels of container is always higher than at upper levels. Calculation of radii R1 and R in inner and outer surfaces of ball segment and their mutual location is done with account of such factors as temperature of heating element, thickness of container walls, distance from heating element to container walls, thickness of gasket, etc. Container lining may be performed directly in container by means of source material pressing in it, or a ball segment may be produced separately, on a special accessory, and may be installed into container, i.e. may be arranged as detachable. Installation of gasket 9 from tantalum prevents penetration of graphite from container into source vapours. ^ EFFECT: possibility to replace source after its exhaustion to a new one. ^ 2 cl, 1 dwg |
