A wavelength conversion device including a cavity that includes an RAMO.sub.4 crystal having a single crystal represented by a first general formula of RAMO.sub.4, a laser crystal, and a mirror, in which in the first general formula, R represents one or a plurality of trivalent elements selected from the group consisting of Sc, In, Y, and lanthanoid elements, A represents one or a plurality of trivalent elements selected from the group consisting of Fe (III), Ga, and Al, and M represents one or a plurality of divalent elements selected from the group consisting of Mg, Mn, Fe (II), Co, Cu, Zn, and Cd.

A crystal growing system includes a rotating seed lift assembly to rotate and lift a seed crystal supported by a cable. The seed lift assembly includes a spool that rotates to wrap the cable around the spool, thus raising the cable. As the spool rotates, it moves in an axial direction to avoid displacing the cable in the axial direction. A leadscrew in a counterweight assembly is mechanically coupled to the spool via a coupling (e.g., a sprocket-and-chain coupling coupled to the spool spindle). As the spool rotates, the leadscrew thus rotates at a rate proportional to the spool's rate of rotation. A movable counterweight driven by the leadscrew is thus driven to move in a direction opposite the axial direction (e.g., opposite the movement of the spool). The counterweight assembly is thus configured to offset center-of-mass changes that would have otherwise been introduced by movement of the spool.

A wavelength conversion device including a cavity that includes an RAMO.sub.4 crystal having a single crystal represented by a first general formula of RAMO.sub.4, a laser crystal, and a mirror, in which in the first general formula, R represents one or a plurality of trivalent elements selected from the group consisting of Sc, In, Y, and lanthanoid elements, A represents one or a plurality of trivalent elements selected from the group consisting of Fe (III), Ga, and Al, and M represents one or a plurality of divalent elements selected from the group consisting of Mg, Mn, Fe (II), Co, Cu, Zn, and Cd.

A crystal growing system can include a spool-balanced seed lift assembly for rotating and lifting a seed crystal supported by a cable. The seed crystal is supported along and rotated about a lift axis. The spool-balanced seed lift assembly includes a spool that rotates on, and has a center of gravity along, an axis that intersects the lift axis. As the spool rotates, it moves axially along its axis to avoid displacing the cable from the lift axis. A guide pulley positioned below the spool is used to direct the cable between the lift axis and a spool-tangent axis to minimize displacement of the cable as it is raised and rotated.

The present invention relates a method for controlling a growth interface shape while growing a monocrystal ingot by a Czochralski method, the method including a step of starting a growth of the monocrystal ingot after setting a control condition of a monocrystal growing process so that an interface of the ingot becomes a target shape; a step of deriving a measurement value by measuring a weight of the ingot grown for a predetermined time by means of a load cell disposed on an upper portion the monocrystal ingot; a step of deriving a theoretical value of the weight of the monocrystal ingot through a diameter of the monocrystal ingot measured by a diameter measuring camera disposed outside of a process chamber for a predetermined time and a height of the monocrystal ingot grown for the predetermined time; a step of predicting a growth interface shape of a growing monocrystal ingot by deriving a difference between the measurement value and the theoretical value; and changing process conditions during growth of the monocrystal ingot by comparing the predicted interface shape of the monocrystal ingot with the targeted interface shape of the monocrystal ingot. Therefore, the interface shape of the growing ingot may be predicted during the growing process of the monocrystal ingot, and the process conditions may be controlled to grow the silicon ingot in the targeted interface shape.

The present invention relates a method for controlling a growth interface shape while growing a monocrystal ingot by a Czochralski method, the method including a step of starting a growth of the monocrystal ingot after setting a control condition of a monocrystal growing process so that an interface of the ingot becomes a target shape; a step of deriving a measurement value by measuring a weight of the ingot grown for a predetermined time by means of a load cell disposed on an upper portion the monocrystal ingot; a step of deriving a theoretical value of the weight of the monocrystal ingot through a diameter of the monocrystal ingot measured by a diameter measuring camera disposed outside of a process chamber for a predetermined time and a height of the monocrystal ingot grown for the predetermined time; a step of predicting a growth interface shape of a growing monocrystal ingot by deriving a difference between the measurement value and the theoretical value; and changing process conditions during growth of the monocrystal ingot by comparing the predicted interface shape of the monocrystal ingot with the targeted interface shape of the monocrystal ingot. Therefore, the interface shape of the growing ingot may be predicted during the growing process of the monocrystal ingot, and the process conditions may be controlled to grow the silicon ingot in the targeted interface shape.

In accordance with the present invention, taught is a high purity germanium crystal growth method utilizing a quartz shield inside a steel furnace. The quartz shield is adapted for not only guiding the flow of an inert gas but also preventing the germanium melt from contamination by insulation materials, graphite crucible, induction coil and stainless steel chamber. A load cell provides automatic control of crystal diameter and helps to ensure exhaustion of the germanium melt. The method is both convenient and effective at producing high purity germanium crystals by relatively low skilled operators.

In accordance with the present invention, taught is a high purity germanium crystal growth method utilizing a quartz shield inside a steel furnace. The quartz shield is adapted for not only guiding the flow of an inert gas but also preventing the germanium melt from contamination by insulation materials, graphite crucible, induction coil and stainless steel chamber. A load cell provides automatic control of crystal diameter and helps to ensure exhaustion of the germanium melt. The method is both convenient and effective at producing high purity germanium crystals by relatively low skilled operators.

A single crystal pulling apparatus including: a remelting detection apparatus which detects that remelting of a lower end portion of the semiconductor single crystal is completed from a change in weight of the semiconductor single crystal when the lower end portion of the semiconductor single crystal is immersed in the melt to be remolten by using the wire; and a lowermost end detection apparatus which detects a lowermost end of the semiconductor single crystal from a position where no current flows between the semiconductor single crystal and the melt when the semiconductor single crystal is taken up with the use of the wire while applying a voltage between the semiconductor single crystal and the melt by applying a voltage between the crucible and the wire.

A single crystal pulling apparatus including: a remelting detection apparatus which detects that remelting of a lower end portion of the semiconductor single crystal is completed from a change in weight of the semiconductor single crystal when the lower end portion of the semiconductor single crystal is immersed in the melt to be remolten by using the wire; and a lowermost end detection apparatus which detects a lowermost end of the semiconductor single crystal from a position where no current flows between the semiconductor single crystal and the melt when the semiconductor single crystal is taken up with the use of the wire while applying a voltage between the semiconductor single crystal and the melt by applying a voltage between the crucible and the wire.