Single crystal ingot pulling machine taking high-power laser beam as auxiliary heating source

Abstract

A single crystal ingot pulling machine includes a crucible for containing a melt. A single crystal ingot is grown from the melt. A laser system selectively transmits a laser beam to the ingot edge. A controller selectively controls the power of the laser to heat the ingot edge such that the local temperature of the edge region increases.

Description

[0001] Cross-reference

[0002] This application claims priority to U.S. Provisional Application No. 63 / 386,743, filed on December 9, 2022, the entire disclosure of which is hereby incorporated herein by reference in its entirety. Technical Field

[0003] The field generally relates to the production of silicon ingots, and more specifically, to an auxiliary heating source for a crystal pulling machine. Background Art

[0004] Growing a crystal using the Czochralski method (CZ) requires precise and stable temperature regulation of the melt in the crucible from which the crystal is pulled. A crystal pulling machine typically includes side heaters positioned around the crucible to achieve a stable temperature of the crucible and the silicon melt. These side heaters radiate heat into the hot zone of the crystal pulling machine, which at least includes the crucible and the growth chamber.

[0005] To achieve low impurity crystal growth, the temperature within the hot zone must be maintained at a consistent high temperature by operating the side heaters at high power output. However, operating at high temperatures degrades components (such as the pedestal, side guards, etc.) within the hot zone and reduces the operating life of the side heaters. Lowering the temperature of the hot zone can introduce impurities. There is a need to selectively regulate the temperature within the hot zone while maintaining low impurity crystal growth.

[0006] This background section is intended to introduce to the reader various aspects of the technology that may be related to various aspects of the present disclosure described and / or claimed below. It is believed that this discussion will help the reader to provide background information to better understand the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light and not as an admission of prior art. Summary of the Invention

[0007] In one aspect, a single crystal pulling machine includes a crucible for containing a melt and a single crystal ingot that at least partially grows from the melt. The ingot has a body defining an outer surface, and the outer surface of the ingot contacts a top surface of the melt defining an ingot edge. The pulling machine further includes a heater at least partially surrounding the crucible and the ingot, a laser system selectively transmitting a laser beam to the ingot edge, and a controller connected to the laser and the heater and selectively controlling the power of the laser and the heater.

[0008] In another aspect, a single crystal ingot pulling machine includes a crucible for containing a melt and a heater that at least partially surrounds the crucible and the ingot. The ingot pulling machine further includes a laser system for selectively transmitting a laser beam to a first region of the surface of the melt, and a controller connected to the laser and the heater and selectively controlling the power of the laser and the heater. The controller is programmed to control the laser to direct the beam to the first region of the surface of the melt, and to control the laser to increase the power of the beam to heat the region such that the local temperature of the first region increases.

[0009] Another aspect is a method of controlling edge band defects in an ingot being pulled in a crystal ingot pulling machine. The crystal ingot pulling machine includes a crucible for containing a melt and a heater operable at a first temperature. The method includes pulling the ingot from the melt, emitting a high power laser beam from a laser to an ingot edge defined by an outer surface of the ingot in contact with a top surface of the melt, and increasing the power of the beam to heat the ingot edge such that the local temperature gradient of the ingot edge increases. Increasing the local temperature gradient of the ingot edge reduces edge band defects in the ingot.

[0010] There are various improvements to the features mentioned in the above aspects of the present disclosure. Further features may also be incorporated into the above aspects of the present disclosure. These improvements and additional features may exist individually, or may exist in any combination. For example, the various features discussed below with respect to any illustrated embodiment of the present disclosure may be incorporated into any of the above aspects of the present disclosure individually or in any combination. Description of the Drawings

[0011] Figure 1 is a cross-sectional view of an ingot pulling machine apparatus for pulling a single crystal ingot from a silicon melt.

[0012] Figure 2 is a cross-sectional view of a portion of another ingot pulling machine apparatus for pulling a single crystal ingot from a silicon melt.

[0013] Figure 3 is a partial front view of a single crystal ingot grown by the Czochralski method.

[0014] Figure 4 is for Figure 1 a simplified block diagram of a computing device in a control system of an exemplary ingot pulling machine apparatus.

[0015] Figure 5 is a cross-sectional view of a portion of another ingot pulling machine apparatus for pulling a single crystal ingot from a silicon melt.

[0016] Figure 6 and 7It is a side view of the crucible and side heater of a pulling machine device.

[0017] Figure 8 It is a flowchart of a method for controlling edge band defects of an ingot pulled in a crystal pulling machine.

[0018] Figure 9 It is a flowchart of a method for controlling the surface temperature of a melt in a crucible of a crystal pulling machine.

[0019] Like reference numerals in the various figures indicate like elements. Detailed Description

[0020] Figure 1 It is a cross-sectional view of a pulling machine, generally designated by "100", for pulling or growing a single crystal ingot from a silicon melt (the pulling machine may be referred to as a pulling machine or a crystal pulling machine). Figure 2 It is a cross-sectional view of a pulling machine device 100, and Figure 3 It is a partial front view of a single crystal silicon ingot grown, for example, by the Czochralski method in a pulling machine device 100.

[0021] The pulling machine 100 includes a crystal pulling machine housing 108 that defines a growth chamber 152 for pulling a silicon ingot 113 from a melt 104 of silicon. A controller 172 controls the operation of the pulling machine 100 and its components. The pulling machine device 100 includes a crucible 102 disposed within the growth chamber 152 for holding a melt 104 of a molten material such as silicon. The crucible 102 is supported by a base 106.

[0022] The crucible 102 includes a bottom plate 129 and side walls 131 extending upward from the bottom plate 129. In this embodiment, the side walls 131 are generally vertical. The bottom plate 129 includes a curved portion of the crucible 102 that extends beneath the side walls 131. Within the crucible 102 is a silicon melt 104 having a melt surface 111 (i.e., the melt-ingot interface). The base 106 is supported by a shaft 105. The base 106, crucible 102, shaft 105, and ingot 113 have a common longitudinal axis A or "pulling axis" A.

[0023] The pulling mechanism 114 is disposed within the ingot pulling machine apparatus 100 for growing and pulling an ingot 113 from a melt 104. The pulling mechanism 114 includes a pulling cable 118, a seed holder or chuck 120 coupled to one end of the pulling cable 118, and a seed 122 attached to the seed holder or chuck 120 for initiating crystal growth. One end of the pulling cable 118 is connected to a pulley (not shown) or a drum (not shown) within the pulling mechanism 114, or any other suitable type of lifting mechanism, such as a shaft, and the other end is connected to the chuck 120 that holds the seed 122. In operation, the seed 122 is lowered to contact the melt 104. The pulling mechanism 114 is operated to raise the seed 122. This causes a single crystal ingot 113 to be pulled from the melt 104.

[0024] During heating and crystal pulling, the crucible drive unit 107 (e.g., a motor) rotates the crucible 102 and the base 106. During the growth process, the lifting mechanism 112 raises and lowers the crucible 102 along the pulling axis A. As the ingot grows, the melt 104 is consumed and the height of the melt in the crucible 102 decreases. The crucible 102 and the base 106 can be raised to maintain the melt surface 111 at the same or a near-same position relative to the ingot pulling machine apparatus 100.

[0025] The ingot pulling machine apparatus 100 can include an inert gas system for introducing and evacuating an inert gas, such as argon, into and out of the growth chamber 152. The ingot pulling machine apparatus 100 can also include a dopant feed system (not shown) for introducing a dopant into the melt 104.

[0026] According to the Czochralski single crystal growth process, a certain amount of polycrystalline silicon or polysilicon is loaded into the crucible 102 (e.g., loaded with 250 kg or more). A variety of polysilicon sources can be used, including, for example, granular polysilicon produced by thermal decomposition of silane or halogenated silane in a fluidized bed reactor or polysilicon produced in a Siemens reactor. Once the polysilicon is added to the crucible to form a charge, the charge is heated to a temperature approximately above the melting temperature of silicon (e.g., about 1412 °C) to heat the charge. In some embodiments, the charge (i.e., the resulting melt) is heated to a temperature of at least about 1425 °C, at least about 1450 °C, or even at least about 1500 °C. The ingot pulling machine 100 includes a bottom insulator 110 and a side insulator 124 to retain heat within the ingot pulling machine apparatus 100. In the illustrated embodiment, the ingot pulling machine apparatus 100 includes a bottom heater 126 disposed below the crucible bottom plate 129.

[0027] To form an ingot, a seed 122 contacts the surface 111 of a melt 104. A lift mechanism 114 is operated to lift the seed 122 from the melt 104. The ingot 113 includes a crown 142, in which the ingot transitions outwardly from the seed 122 and tapers to a target diameter. The ingot 113 includes a constant diameter portion 145 or cylindrical "body" of the crystal, which is grown by increasing the lift rate. The body 145 of the ingot 113 has a relatively constant diameter. The ingot 113 includes a tail or end cone (not shown), in which the ingot tapers in diameter after the body 145. The ingot puller apparatus 100 includes a side heater 135 and a pedestal 106, which surround the crucible 102 to maintain the temperature of the melt 104 during crystal growth. When the crucible 102 travels up and down along the lift axis A, the side heater 135 is disposed radially outwardly of the crucible sidewall 131. The side heater 135 and the bottom heater 126 can be any type of side heater that allows the side heater 135 and the bottom heater 126 to operate as described herein. In some embodiments, the heaters 135, 126 are resistive side heaters. The side heater 135 and the bottom heater 126 can be controlled by a control system 172 such that the temperature of the melt 104 is controlled throughout the lift process.

[0028] The ingot puller apparatus 100 may further include a reflector 151 (or "heat shield"), which is disposed within the growth chamber 152 and above the melt 104 and covers the ingot 113 during ingot growth. During crystal growth, the reflector 151 may be partially disposed within the crucible 102. The reflector 151 defines a central passage 160 for receiving the ingot 113 as the ingot is lifted by the lift mechanism 114.

[0029] The reflector 151 can be a heat shield adapted to retain heat below it and above the melt 104. Other reflector designs and construction materials (such as graphite) can be used without limitation. The reflector 151 has a bottom 138 (as Figure 2 best shown), and the bottom 138 of the reflector 151 is separated from the surface of the melt by a distance HR during ingot growth. As the ingot 113 is lifted, the distance HR increases due to the consumption of the melt 104.

[0030] In Figure 4 is shown an example single crystal silicon ingot 113 produced by the Czochralski method. The ingot 113 includes a neck 116, a flared-out portion 142 (synonym "crown" or "cone"), a shoulder 119, and a constant diameter body 145. The neck 116 is attached to the seed 122, which contacts the melt and is withdrawn to form the ingot 113. The body 145 is suspended from the neck 116. Once the tapered portion 142 of the ingot 113 begins to form, the neck 116 terminates.

[0031] The constant diameter portion 145 of the ingot 113 has a circumferential edge 150, a central axis A parallel to the circumferential edge 150, and a radius R extending from the central axis A to the circumferential edge 145. The central axis A also passes through the tapered portion 142 and the neck 116. The diameter of the ingot body 145 can vary and, in some embodiments, can be about 150 mm, about 200 mm, about 300 mm, greater than about 300 mm, about 450 mm, or even greater than about 450 mm.

[0032] The single crystal silicon ingot 113 can generally have any resistivity. The single crystal silicon ingot 113 can be doped or undoped.

[0033] Figure 4 is an example computing device 400 that can be used as the control system 172 or as part of the control system 172. The computing device 400 includes a processor 402, a memory 404, a media output component 406, an input device 408, and a communication interface 410. Other embodiments may include different components, additional components, and / or not include Figure 4 all of the components shown. The processor 402 is configured to execute instructions. In some embodiments, the executable instructions are stored in the memory 404. The processor 402 may include one or more processing units (e.g., in a multi-core configuration). As used herein, the term processor refers to a central processing unit, a microprocessor, a microcontroller, a reduced instruction set circuit (RISC), an application specific integrated circuit (ASIC), a programmable logic circuit (PLC), and any other circuit or processor capable of performing the functions described herein. The foregoing are merely examples and are not intended to limit in any way the definition and / or meaning of the term "processor". The memory 404 stores non-transitory computer-readable instructions for performing the techniques described herein. Such instructions, when executed by the processor 402, cause the processor 402 to perform at least a portion of the methods described herein. In some embodiments, the memory 404 stores computer-readable instructions for providing a user interface to a user via the media output component 406 and receiving and processing inputs from the input device 408.

[0034] The memory 404 may include, but is not limited to, random access memory (RAM), such as dynamic RAM (DRAM) or static RAM (SRAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and non-volatile RAM (NVRAM). Although illustrated as separate from the processor 402, in some embodiments, the memory 404 is combined with the processor 402, such as in a microcontroller or microprocessor, but may still be referred to separately. The above memory types are merely examples and are thus not limited to the types of memory that can be used to store computer programs. The media output component 406 is configured to present information to a user (e.g., an operator of the system). The media output component 406 is any component capable of communicating information to a user. In some embodiments, the media output component 406 includes output adapters such as, for example, a video adapter and / or an audio adapter. The output adapter is operatively connected to the processor 402 and is operatively connectable to an output device, such as a display device (e.g., a liquid crystal display (LCD), a light-emitting diode (LED) display, an organic light-emitting diode (OLED) display, a cathode ray tube (CRT), an "electronic ink" display, one or more light-emitting diodes (LEDs)) or an audio output device (e.g., a speaker or headphones).

[0035] The computing device 400 includes or is connected to an input device 408 for receiving input from a user. The input device 408 is any device that allows the computing device 400 to receive analog and / or digital commands, instructions, or other input from a user, including visual, audio, touch, button presses, stylus taps, etc. The input device 408 may include, for example, a variable resistor, an input dial, a keyboard / keypad, a pointing device, a mouse, a stylus, a touch-sensitive panel (e.g., a touchpad or a touchscreen), a gyroscope, an accelerometer, a position detector, an audio input device, or any combination thereof. A single component, such as a touchscreen, can be used both as an output device of the media output component 406 and as an input device 408.

[0036] The communication interface enables the computing device 400 to communicate with remote devices and systems, such as remote sensors, remote databases, remote computing devices, etc., and may include more than one communication interface for interacting with more than one remote device or system. The communication interface may be a wired or wireless communication interface that allows the computing device 400 to communicate directly or via a network with remote devices and systems. The wireless communication interface may include a radio frequency (RF) transceiver, an adapter, a Wi-Fi transceiver, A transceiver, a Near Field Communication (NFC) transceiver, an Infrared (IR) transceiver, and / or any other device and communication protocol for wireless communication. (Bluetooth is a registered trademark of the Bluetooth Special Interest Group in Kirkland, Washington; ZigBee is a registered trademark of the ZigBee Alliance in San Ramon, California.) The wired communication interface can perform direct communication using any suitable wired communication protocol, including but not limited to USB, RS232, I2C, SPI, analog, and proprietary I / O protocols. In some embodiments, the wired communication interface includes a wired network adapter that allows the computing device 400 to be coupled to a network, such as the Internet, a Local Area Network (LAN), a Wide Area Network (WAN), a mesh network, and / or any other network, to communicate with remote devices and systems via the network. The computer systems discussed herein may include additional, fewer, or alternative functions. The computer systems discussed may include computer-executable instructions stored on one or more non-transitory computer-readable media or implemented via the computer-executable instructions.

[0037] As Figure 1 and 4 shown, the ingot pulling machine device includes a laser system 170 for selectively transmitting a laser beam to the circumferential edge 150 of the ingot. As Figure 2 shown, the laser system 170 can be used to increase the power of the laser beam to heat the ingot edge 150, so as to increase the local temperature gradient of the ingot edge 150. By selectively heating the ingot edge 150 at or near the melt surface 111 (i.e., the melt-ingot interface), the defects generated in the ingot during the crystal growth process can be controlled. In addition, the methods and systems described herein allow the side heater 135 to operate at a lower temperature.

[0038] The laser system 170 and the controller 172 define an auxiliary heating system. The controller 172 uses the laser system 170 to direct the position of the laser beam to heat the ingot edge 150 and set the power output for the laser system 170. The laser system 170 includes a high-power laser 190 that is mounted on a track 192 to allow positioning of the laser 190. The laser 190 and the track 192 are positioned outside the growth chamber 152. The laser 208 has a laser power in the range of 1KW to 3KW, a wavelength of 520nm, a diode laser with a divergence of <0.3 and a beam size of 3mm, and is capable of delivering focused radiant heat to the target area.

[0039] To use the auxiliary heating system, the laser 190 is directed at a region near or adjacent to the interface between the ingot edge 150 and the melt surface 111. The laser 190 is controlled to increase the power of the beam to heat the ingot edge 150 such that the local temperature gradient of the ingot edge is increased. Increasing the local temperature gradient of the ingot edge 150 reduces edge band defects in the ingot, as further explained in detail below. The laser 190 can travel along a track 192 such that the beam is selectively directed to a region 10 mm to 20 mm from the ingot edge. The track 192 can be vertical, horizontal, or angled. In an alternative embodiment, the laser 190 is attached to a gimbal or robotic arm to position the laser 190 and adjust the position where the beam is directed to heat the ingot edge 150.

[0040] The laser beam has a first width and a second width, and the second width is greater than the first width. The second width heats a larger surface area of the ingot edge 150. The width of the beam is appropriately adjusted by changing the focal length of the laser 190. In some embodiments, the second width is 10 mm greater than the first width.

[0041] The width of the laser beam can remain constant and be narrower relative to the first width and the second width (referred to as a "point beam"). The laser 190 can continuously travel up and down along the track 192 through a cycling distance such that when the ( Figure 1 ) ingot 113 is lifted and rotated, the point beam distributes the focused narrow beam across a larger region of the ingot edge 150. The cycling of the laser 190 produces a sinusoidal beam pattern on the ingot 113 that has an amplitude that is half of the cycling distance. In some embodiments, the cycling distance is 10 mm. In some embodiments, the cycling distance is 20 mm. In some embodiments, the cycling distance is in the range of 5 mm to 50 mm.

[0042] When the laser 190 is not emitting a beam, the ingot can be lifted at a first rate, and the auxiliary heating system, e.g., heating the ingot edge 150 with a laser beam, can be used to lift the ingot at a second rate. The second rate is faster than the first rate. By heating the ingot edge 150 with the auxiliary heating system, the edge band defects in the ingot do not increase relative to the edge band defects that typically occur at the first rate. In some embodiments, the edge band defects are the same or approximately the same at the first rate and the second rate.

[0043] Similarly, when the laser 190 does not emit a beam to the ingot edge 150, the side heater 135 can operate at a first temperature, and when the laser 190 emits a beam to the ingot edge 150, the side heater 135 can operate at a second and lower temperature. Thus, by operating the laser 190 to emit a beam, the side heater 135 can operate at a lower temperature, which reduces the degradation of components in the hot zone and increases the operating life of the side heater 135, while reducing edge band defects in the ingot.

[0044] As Figure 2 shown, operating the laser 190 to emit a beam to heat the ingot edge 150 enables pulling the crystal with a smaller gap G between the melt surface 111 and the bottom edge 153 of the reflector 151. Since the side heater 135 can operate at a lower temperature when the laser 190 emits a beam to the ingot edge 150, the reflector 151 can be positioned closer to the melt surface 111. In prior art systems and methods, this positioning would degrade the reflector 151 due to the heat from the side heater 135 during normal operation. Positioning the reflector 151 closer to the melt surface 111 increases the local temperature gradient at the ingot edge 150 and reduces edge band defects in the ingot when pulling the ingot.

[0045] In addition, by reducing the gap G between the melt surface 111 and the bottom edge 153 of the reflector 151, the cooling rate of the entire ingot is increased. It is desirable to increase the cooling rate near the triple point (near the ingot edge 150) of the ingot because it allows pulling the ingot at a faster rate. In the absence of the operation of the laser 190 emitting a beam to heat the ingot edge 150, reducing the gap G between the melt surface 111 and the bottom edge 153 of the reflector 151 increases edge band defects in the ingot because the temperature gradient is no longer optimal. Operating the laser 190 keeps the temperature gradient within the optimal range while reducing the gap G between the melt surface 111 and the bottom edge 153 of the reflector 151 to increase or maintain the pulling rate.

[0046] Edge band formation is a defect introduced by point defect kinetics in the ingot. To mitigate or control edge band defect formation, the temperature gradient at the triple point in the region near or adjacent to the interface between the ingot edge 150 and the melt surface 111. The laser beam controls the temperature gradient in the region heated by the laser beam. Thus, through this process, the point defect distribution in the ingot will change and edge band formation will be reduced. This process can be further optimized by adjusting the precise position of the beam irradiation or by changing the width of the laser beam. The power of the beam controls the triple point of the region where the beam is directed.

[0047] As Figure 1As shown, the controller 172 is connected to the laser 190 and the side heater 135, and can be programmed to perform at least the following functions. The laser 208 is controlled to direct a laser beam to the ingot edge 150 and increase the power of the beam to heat the ingot edge 150 such that the local temperature gradient of the ingot edge 150 increases. In some embodiments, the controller is further programmed to reduce the power output of the side heater 135.

[0048] In Figure 5 an alternative embodiment shown, the laser 290 mounted on the track 192 directs a beam to an area of the surface melt 111. The laser 290 can be used independently or in combination with the laser 190, where the laser 190 directs a beam to the crystal edge 150. The laser 290 directs a laser beam to a first region R1 of the surface melt 111. Similar to the laser 190, the laser 290 selectively increases the temperature of the surface at the first region R1 such that the side heater can operate at a lower temperature.

[0049] The laser 290 can be positioned such that the beam is selectively transmitted along the melt surface 111 to a second region that is 10 mm to 20 mm from the first region. Additionally, the beam can be adjusted to have a first width and a second width, where the second width is greater than the first width, and the second width is configured to heat a larger surface area of the melt surface. In some embodiments, the second width is 10 mm greater than the first width.

[0050] Figure 6 and 7 illustrate the temperature gradients 702 to 720 (in grayscale) of the melt 104. As Figure 6 shown, the side heater 135 operates to radiate a first temperature to the melt 104, and the melt 104 has a generally uniform temperature. As Figure 7 shown, the temperature gradients 702, 704, 706, 708, 710, 712, 714, 716, 718, and 720 are depicted in order of decreasing temperature. Gradient 702 has the highest temperature in the gradients at 1,713.6 degrees Kelvin, and gradient 720 has the lowest temperature in the gradients at 1,676.6 degrees Kelvin. By directing the beam from the laser 290 to the surface 111, the surface 111 around the center has a higher local temperature, allowing the side heater 135 to operate at a second temperature lower than the first temperature. By reducing the temperature of the side heater 135, the oxygen concentration in the melt 104 and the crystal is also reduced. This further facilitates increasing seed lift, controlling crystal diameter, reducing crystal deformation, and controlling the melt-crystal interface shape.

[0051] Figure 8Disclosed is an example method 300 for controlling edge band defects in an ingot pulled in a crystal pulling machine. The method includes the steps of pulling 302 an ingot from a melt; emitting 304 a high-power laser beam from a laser to an ingot edge defined by an outer surface of the ingot in contact with a top surface of the melt; and increasing 306 the power of the beam to heat the ingot edge such that a local temperature gradient of the ingot edge is increased, wherein increasing the local temperature gradient of the ingot edge reduces edge band defects in the ingot. The method may further include reducing 308 the temperature of the heater from a first temperature to a second temperature, the second temperature being lower than the first temperature, wherein the edge band defects in the ingot at the first temperature of the heater are the same as the edge band defects in the ingot at the temperature.

[0052] Figure 9 The example method 600 shown in FIG. includes controlling the surface temperature of a melt in a crucible of a crystal pulling machine, the crystal pulling machine including a heater. The method includes the steps of emitting 602 a high-power laser beam from a laser to a region of the surface of the melt, and increasing 604 the power of the beam to heat the region of the surface of the melt. Method 600 may further include reducing 606 the temperature of the heater from a first temperature to a second temperature, the second temperature being lower than the first temperature.

[0053] The embodiments described herein provide the ability to control the triple point between the ingot edge and the melt surface. The embodiments described herein provide an auxiliary heat source in the form of a high-power laser beam that is directed to the ingot edge and the melt surface. Another advantage of using the embodiments described herein is the problem associated with premature wear of components of the crystal pulling machine due to excessive thermal exposure from side heaters. By controlling the triple point between the ingot edge and the melt surface with an auxiliary heat source, the side heaters can operate at a lower temperature while still reducing edge bad defects in the ingot. Accordingly, the components of the crystal pulling machine are less exposed to extreme heat.

[0054] When introducing elements of the present disclosure or its embodiments, the articles “a,” “an,” and “the” and “said” are intended to mean that there is one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. The use of terms indicating a particular orientation (e.g., “top,” “bottom,” “side,” “down,” “up,” etc.) is for ease of description and does not require any particular orientation of the item being described.

[0055] Various changes may be made to the above-described configurations and methods without departing from the scope of the present disclosure, and all of the content included in the above description and shown in the drawings should be construed as illustrative rather than restrictive.

Claims

1. A single crystal ingot pulling machine, comprising: A crucible for containing a melt; A single crystal ingot that grows at least partially from the melt, the ingot having a body defining an outer surface, and the outer surface of the ingot contacting a top surface of the melt that defines an ingot edge; A heater that at least partially surrounds the crucible and the ingot; A laser system for selectively transmitting a laser beam to the ingot edge; And A controller connected to the laser and the heater and selectively controlling the power of the laser and the heater.

2. The crystal ingot pulling machine according to claim 1, wherein the controller is programmed to: Control the laser to direct the laser beam to the ingot edge; and Control the laser to increase the power of the beam to heat the ingot edge, such that the local temperature gradient at the ingot edge increases; Wherein increasing the local temperature gradient at the ingot edge reduces edge band defects in the ingot.

3. The crystal ingot pulling machine according to claim 1, wherein the laser is configured to selectively direct the beam to an area 10 mm to 20 mm from the ingot edge.

4. The crystal ingot pulling machine according to claim 1, wherein the beam has a first width and a second width, the second width being greater than the first width, and the second width heating a larger surface area of the ingot edge.

5. The crystal ingot pulling machine according to claim 4, wherein the second width is 10 mm greater than the first width.

6. The crystal ingot pulling machine according to claim 1, wherein the laser power is in the range of 1 KW to 3 KW.

7. The crystal ingot pulling machine according to claim 1, wherein when the laser does not emit the beam, the ingot is pulled at a first rate, and wherein when the laser emits the beam to the ingot edge, the crystal ingot is pulled at a second rate, and wherein the second rate is greater than the first rate.

8. The crystal ingot pulling machine according to claim 7, wherein the edge band defects in the ingot at the first rate are the same as the edge band defects in the ingot at the second rate.

9. The crystal ingot pulling machine according to claim 1, wherein the laser is attached to a track for continuously cycling the laser up and down along the track by a certain cycle distance.

10. The crystal ingot pulling machine according to claim 9, wherein the laser produces a sine beam pattern on the ingot, the pattern having an amplitude equal to half of the cycle distance.

11. The crystal ingot pulling machine according to claim 9, wherein the cycle distance is in the range of 10 mm to 20 mm.

12. The crystal ingot pulling machine according to claim 1, wherein when the laser does not emit the beam to the ingot edge, the controller operates the heater at a first temperature, and wherein when the laser emits the beam to the ingot edge, the controller operates the heater at a second temperature, wherein the second temperature is lower than the first temperature.

13. The crystal pulling ingot machine according to claim 12, wherein the edge band defects in the ingot edge at the first temperature of the heater are the same as the edge band defects in the ingot edge at that temperature.

14. The crystal pulling ingot machine according to claim 12, wherein the bottom edge of the reflector positioned within the ingot machine is positioned at a first distance from the melt at the first temperature of the heater and at a second distance from the melt at the second temperature of the heater, the second distance being greater than the first distance.

15. The crystal pulling ingot machine according to claim 14, wherein the power of the light beam controls the triple point of the region where the light beam is guided.

16. A single crystal pulling ingot machine, comprising: a crucible for containing a melt; a heater at least partially surrounding the crucible and the ingot; a laser system for selectively transmitting a laser beam to a first region of the surface of the melt; and a controller connected to the laser and the heater and selectively controlling the power of the laser and the heater; the controller being programmed to: control the laser to direct the light beam to the first region of the surface of the melt; and control the laser to increase the power of the light beam to heat the region such that the local temperature of the first region increases.

17. The crystal pulling ingot machine according to claim 16, wherein the laser is configured to selectively transmit the light beam to a second region 10 mm to 20 mm away from the first region.

18. The crystal pulling ingot machine according to claim 16, wherein the light beam has a first width and a second width, the second width being greater than the first width, the second width being configured to heat a larger surface area of the surface of the melt.

19. The crystal pulling ingot machine according to claim 18, wherein the second width is 10 mm greater than the first width.

20. The crystal pulling ingot machine according to claim 16, wherein the power is in the range of 1 KW to 3 KW.

21. The crystal pulling ingot machine according to claim 16, wherein when the laser does not emit the light beam to the first region, the controller operates the heater at a first temperature, and wherein when the laser emits the light beam to the first region, the controller operates the heater at a second temperature, the second temperature being lower than the first temperature.

22. A method of controlling edge band defects of an ingot pulled in a crystal pulling ingot machine, the crystal pulling ingot machine including a crucible for containing a melt and a heater operating at a first temperature, the method comprising: pulling the ingot from the melt; emitting a high-power laser beam from a laser to an ingot edge defined by an outer surface of the ingot that contacts the top surface of the melt; and increasing the power of the light beam to heat the ingot edge such that the local temperature gradient of the ingot edge is increased, wherein increasing the local temperature gradient of the ingot edge reduces the edge band defects in the ingot.

23. The method according to claim 22, further comprising reducing the temperature of the heater from the first temperature to a second temperature, the second temperature being lower than the first temperature, wherein the edge band defects in the ingot at the first temperature of the heater are the same as the edge band defects in the ingot at the temperature.

24. A method of controlling the surface temperature of a melt in a crucible of a crystal pulling machine, the crystal pulling machine comprising a heater that operates at a first temperature, the method comprising: Emitting a high-power laser beam from a laser to an area of the surface of the melt; And Increasing the power of the beam to heat the area of the surface of the melt such that the local temperature gradient at the ingot edge of the ingot is increased; Wherein increasing the local temperature gradient at the ingot edge reduces edge band defects in the ingot.

25. The method according to claim 24, further comprising reducing the temperature of the heater from the first temperature to a second temperature, the second temperature being lower than the first temperature.

26. The method according to claim 24, further comprising pulling the ingot at a second rate when the laser emits the beam to the ingot edge, wherein the second rate is greater than a first rate when the laser does not emit the beam.

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