Methods for automatically controlling material suction in a process of pulling-up of a monocrystal

A method for automatically controlling material suction in a process of pulling-up of a monocrystal, comprising:

• obtaining a lifetime value and a resistivity of a pulled monocrystalline silicon rod, and continuing to operate a monocrystalline silicon rod being pulled;
• and
• in response to determining that the lifetime value is less than or equal to the preset lifetime value or/and the ratio of the lifetime value to the resistivity is less than or equal to the preset ratio value, performing a segment-taking and material suction procedure;
• wherein performing the segment-taking and material suction procedure comprises:
• in response to determining that remaining material in a quartz crucible is not within a safety range, stopping pulling of the monocrystalline silicon rod being pulled, and starting to perform a material suction process using a suction tool,
• wherein performing the material suction process comprises performing a stepwise preheating of the suction tool, and performing the stepwise preheating of the suction tool comprises:
• standing and preheating the suction tool at least twice, wherein, as the suction tool descends, the standing and preheating of the suction tool every time is prolonged by 4-10 min than that of a previous time;
• controlling the suction tool to descend towards a liquid surface of molten silicon and determining whether the suction tool is in contact with the liquid surface of molten silicon;
• upon receiving a contact voltage alarm from the suction tool, adjusting the suction tool to be lifted up by 1-5 mm, and standing and preheating the suction tool again for a predetermined time;
• controlling the suction tool to descend towards the liquid surface of molten silicon again and determining whether the suction tool is in contact with the liquid surface of molten silicon again;
• and
• upon receiving the contact voltage alarm from the suction tool again, adjusting a rotational speed of the quartz crucible to 1 r/min, and finishing the stepwise preheating of the suction tool.