Technique and device for low dislocations germanium mono-crystal with crucible lowering down czochralski method

Abstract

The invention discloses a technique and a device for growing low-dislocation germanium single crystals by a crucible-dropping Czochralski method, which belong to the technical field of growing single crystals. The device is a Czochralski furnace. The crucible is fixed on the top of the crucible rod in the center of the furnace body. The main heating element and the bottom heating element are fixed around and at the bottom of the crucible. Around the body, the seed chuck hangs above the crucible. The low-dislocation germanium single crystal is grown by the crucible-dropping Czochralski method. The process flow is to put the high-purity germanium raw material in the crucible, install the seed crystal on the seed crystal chuck, and gradually lower the crucible position during the crystal pulling process. The crystal is self-sustaining. Top-down growth realizes the key technology of necking at a higher crucible position and then lowering the crucible position for crystal pulling under the condition of a small temperature gradient thermal field, which effectively solves the contradiction between necking and dislocation proliferation. Successfully produced large-size (above 4 inches) low-dislocation germanium single crystals to meet the requirements of space-efficient GaAs / Ge solar cell substrates.

Description

technical field [0001] The invention belongs to the technical field of growing single crystals, and in particular relates to a low-dislocation germanium single crystal growth process and device mainly used as a space-efficient GaAs / Ge solar cell substrate by the Czochralski method. Background technique [0002] The Czochralski method, also known as the Czochralski method, is the main method for growing semiconductor single crystals. In the Czochralski single crystal furnace, the seed crystal is introduced into the crucible containing the melt as a non-uniform crystal nucleus, and then the thermal field is controlled to rotate the seed crystal and lift it up slowly, and the single crystal is placed under the seed crystal in the direction of the seed crystal Grow up to obtain the desired single crystal. Generally, in the process of growing a single product by the Czochralski method, the position of the crucible is kept unchanged or the crucible position is raised, and the tem...

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Problems solved by technology

The Czochralski method was invented by Czochralski for growing metal single crystals (Czochralski J.Z PhysChem, 1917, 92: 219), and later Teal and Little transplanted it to germanium single crystal growth (Teal G K, Little J B. PhysRev, 1950, 78: 647 ), the Umicore company in Belgium grows dislocation-free germanium single crystals by the Czochralski method, especially the production technology of large-size substrates that is conducive to reducing battery costs has not yet been published

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