A device and method for preparing gallium arsenide crystal by vgf method

Abstract

The invention provides a device and a method for preparing a gallium arsenide crystal by a VGF process. The device comprises a CGF furnace body, a support body penetrating the bottom of the VGF furnace body, and a lifting platform connected with the support body and provided with a rotary shaft connected to the bottom of the VGF furnace body, wherein a quartz tube and a heater arranged on the outer side of the quartz tube are arranged in the VGF furnace body; the quartz tube consists of an upper tube body and a lower tube body; the diameter of the upper tube body is more than that of the lowertube body; the upper tube body is provided with a first PBN crucible of which the diameter is matched with that of the upper tube body; the lower tube body is provided with a second PBN crucible of which the diameter is matched with that of the lower tube body. According to the device for preparing the gallium arsenide crystal by the VGF process, the structure of the quartz tube is improved, so that one-time sealing is omitted, the service life of the PBN crucible is prolonged, and accordingly, the device is excellent in stability and high in long crystal yield; and meanwhile, through structural improvement of the VGF furnace body, the prepared gallium arsenide crystal is long and has less defects.

Description

technical field [0001] The invention relates to the technical field of gallium arsenide crystal growth, and more specifically relates to a device and method for preparing gallium arsenide crystals by a VGF method. Background technique [0002] Gallium arsenide (GaAs) is the second-generation semiconductor material after Ge and Si. GaAs has some better electronic properties than Si, so that GaAs can be used in occasions higher than 250GHz. If the equivalent GaAs and Si components are operated at high frequencies at the same time, GaAs will generate less noise; also because GaAs has Higher breakdown pressure, so GaAs is more suitable for high power operation than the same Si components. Therefore, GaAs circuits can be used in mobile phones, satellite communications, microwave point-to-point connections, radar systems and other fields, and have broad development prospects. [0003] Traditional methods for mass production of GaAs crystals include liquid-enclosed Czochralski me...

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Problems solved by technology

[0005] However, to prepare GaAs crystals with a large diameter of 4 to 6 inches with the VGF method in the prior art, two PBN crucibles of the same size are required, and a quartz ring is needed to support between the two PBN crucibles. On the one hand, it needs to be sealed twice, and at the same time Both PBN crucibles need to be loaded with polycrystalline material. Due to the collision between the polycrystalline material and the inner wall of the PBN crucible during the charging process, the service life of the PBN crucible is shortened, thereby increasing the instability of the device and affecting the yield of crystal growth; the other On the one hand, limited by the length of the PBN crucible, the 4-inch gallium arsenide crystal prepared by the above-mentioned mature VGF method can grow up to 200mm at most, and the growth time is too fast, resulting in uneven heating, twinning, large thermal stress, and high dislocation density. defect

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