Single crystal ingot pulling apparatus equipped with a high-power laser beam as an auxiliary heating source

Abstract

The single crystal ingot puller 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 an end of the ingot. A controller selectively controls the power of the laser to heat the end of the ingot to increase the local temperature in the ingot end region.

Description

cross reference

[0001] This application claims priority to U.S. Provisional Application No. 63 / 386,743, filed December 9, 2022, the entire disclosure of which is incorporated herein by reference in its entirety. [Technical Field]

[0002] The field relates generally to the production of silicon ingots, and more specifically to supplemental heat sources for crystal ingot pullers. [Background technology]

[0003] Crystal growth using the Czochralski (CZ) method requires precise and stable temperature control of the melt in the crucible from which the crystal is pulled. Crystal ingot pullers generally include side heaters positioned around the crucible to achieve stable temperatures in the crucible and silicon melt. These side heaters radiate heat toward a hot zone in the crystal ingot puller, which includes at least the crucible and the growth chamber. Summary of the Invention [Problem to be solved by the invention]

[0004] To achieve low-impurity crystal growth, the temperature in the hot zone must be maintained continuously at a high temperature by operating the side heaters at high power. However, operating at a high temperature degrades components in the hot zone (susceptor, side shields, etc.) and reduces the operating life of the side heaters. Lowering the temperature in the hot zone can introduce impurities. It is necessary to selectively adjust the temperature in the hot zone while maintaining low-impurity crystal growth.

[0005] This Background section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of 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 admissions of prior art. [Means for solving the problem]

[0006] In one aspect, a single crystal ingot puller includes a crucible for containing a melt and a single crystal ingot at least partially grown from the melt, the ingot having a body defining an outer surface, the outer surface of the ingot contacting an upper surface of the melt defining an ingot edge, 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 coupled to the laser and the heater and selectively controlling the power of the laser and the heater.

[0007] In another aspect, a single crystal ingot puller includes a crucible for containing a melt and a heater at least partially surrounding the crucible and the ingot. The ingot puller further includes a laser system for selectively transmitting a laser beam to a first region of a surface of the melt, and a controller coupled to the laser and the heater for 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 first region to increase a local temperature in the first region.

[0008] Another aspect is a method for controlling edge band defects in a crystal ingot pulled in a crystal ingot puller, the crystal ingot puller including a crucible for containing a melt and a heater operable at a first temperature. The method includes pulling the crystal ingot from the melt, emitting a high-power laser beam from a laser at an edge of the ingot defined by an outer surface of the ingot contacting an upper surface of the melt, and increasing the power of the beam to heat the ingot edge to increase a local temperature gradient at the ingot edge. Increasing the local temperature gradient at the ingot edge reduces edge band defects in the ingot.

[0009] Various refinements exist in the features noted in connection with the foregoing aspects of the present disclosure. Additional features may likewise be incorporated into the foregoing aspects of the present disclosure. These refinements and additional features may exist individually or in any combination. For example, various features described below in connection with any of the illustrated embodiments of the present disclosure may be incorporated alone or in any combination into any of the foregoing aspects of the present disclosure. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of an ingot puller used to pull a single crystal silicon ingot from a silicon melt. [Figure 2] 1 is a cross-sectional view of a portion of another ingot pulling apparatus used to pull a single crystal silicon ingot from a silicon melt. [Figure 3] FIG. 1 is a partial front view of a single crystal silicon ingot grown by the Czochralski method. [Figure 4] FIG. 2 is a simplified block diagram of a computer device for use in the control system of the exemplary ingot pulling apparatus of FIG. 1. [Figure 5] 1 is a cross-sectional view of a portion of another ingot pulling apparatus used to pull a single crystal silicon ingot from a silicon melt. [Figure 6] FIG. 1 is a side view of the crucible and side heater of the ingot puller. [Figure 7] FIG. 1 is a side view of the crucible and side heater of the ingot puller. [Figure 8] 1 is a flow chart of a method for controlling edge band defects in a crystalline ingot pulled in a crystalline ingot puller. [Figure 9] 1 is a flow chart of a method for controlling the surface temperature of a melt in a crucible of a crystal ingot puller.

[0011] Like reference symbols in the various drawings indicate like elements. DETAILED DESCRIPTION OF THE INVENTION

[0012] Figure 1 is a cross-sectional view of an ingot puller (sometimes called an ingot or crystal ingot puller) generally designated "100" that is used to pull or grow a single crystal ingot from a silicon melt. Figure 2 is a cross-sectional view of the ingot puller 100, and Figure 3 is a partial elevational view of a single crystal silicon ingot grown, for example, by the Czochralski method in the ingot puller 100.

[0013] The ingot puller 100 includes a crystalline ingot puller housing 108 that defines a growth chamber 152 for pulling a silicon ingot 113 from a silicon melt 104. A controller 172 controls the operation of the ingot puller 100 and its components. The ingot puller 100 includes a crucible 102 disposed within the growth chamber 152 for holding a melt 104 of molten material, such as silicon. The crucible 102 is supported by a susceptor 106.

[0014] The crucible 102 includes a floor 129 and a sidewall 131 extending upwardly from the floor 129. The sidewall 131 is generally vertical in this embodiment. The floor 129 includes a curved portion of the crucible 102 that extends below the sidewall 131. Within the crucible 102 resides a silicon melt 104 having a melt surface 111 (i.e., a melt-ingot interface). A susceptor 106 is supported by a shaft 105. The susceptor 106, crucible 102, shaft 105, and ingot 113 share a common longitudinal axis A, or "pulling axis," A.

[0015] A pulling mechanism 114 is disposed within the ingot pulling apparatus 100 to grow and pull an ingot 113 from the melt 104. The pulling mechanism 114 includes a pulling cable 118, a seed holder or chuck 120 connected to one end of the pulling cable 118, and a seed crystal 122 attached to the seed holder or chuck 120 to initiate crystal growth. One end of the pulling cable 118 is connected to a pulley (not shown) or drum (not shown) within the pulling mechanism 114, or other suitable type of pulling mechanism, such as a shaft, and the other end is connected to the chuck 120, which holds the seed crystal 122. During operation, the seed crystal 122 is lowered into contact with the melt 104. The pulling mechanism 114 is actuated to raise the seed crystal 122, which causes the single crystal ingot 113 to be pulled from the melt 104.

[0016] During heating and crystal pulling, a crucible drive unit 107 (e.g., a motor) rotates the crucible 102 and susceptor 106. A lift mechanism 112 raises and lowers the crucible 102 along the pulling axis A during the growth process. As the ingot grows, the melt 104 is consumed and the melt height in the crucible 102 decreases. The crucible 102 and susceptor 106 can be raised to maintain the melt surface 111 at or near the same position relative to the ingot pulling apparatus 100.

[0017] The ingot pulling apparatus 100 may include an inert gas system for introducing and withdrawing an inert gas, such as argon, from the growth chamber 152. The ingot pulling apparatus 100 may also include a dopant delivery system (not shown) for introducing dopants into the melt 104.

[0018] According to the Czochralski single crystal growth process, a quantity of polycrystalline silicon, i.e., polysilicon, is charged to the crucible 102 (e.g., a charge of 250 kg or more). Various sources of polycrystalline silicon can be used, including, for example, granular polycrystalline silicon produced by the pyrolysis of silane or halosilane in a fluidized bed reactor, or polycrystalline silicon produced in a Siemens reactor. Once the polycrystalline silicon is added to the crucible to form the charge, the charge is heated to a temperature above the melting temperature of silicon (e.g., about 1412°C) to melt 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 at least about 1500°C. The ingot puller 100 includes bottom insulation 110 and side insulation 124 to retain heat within the puller 100. In the illustrated embodiment, the ingot pulling apparatus 100 includes a bottom heater 126 located below the crucible floor 129 .

[0019] To form an ingot, the seed crystal 122 contacts the surface 111 of the melt 104. A pulling mechanism 114 is activated to pull the seed crystal 122 from the melt 104. The ingot 113 includes a crown portion 142 that tapers outward from the seed crystal 122 as the ingot reaches a target diameter. The ingot 113 includes a constant diameter portion 145, or cylindrical "body," of the crystal that is grown by increasing the pulling rate. The body 145 of the ingot 113 has a relatively constant diameter. The ingot 113 includes a tail or end cone (not shown) where the ingot narrows in diameter after the body 145. The ingot pulling apparatus 100 includes a side heater 135 and a susceptor 106 surrounding the crucible 102 to maintain the temperature of the melt 104 during crystal growth. The side heater 135 is positioned radially outward relative to the crucible sidewall 131 as the crucible 102 moves up and down the pulling axis A. The side heater 135 and the bottom heater 126 can be any type of side heater that enables 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 so that the temperature of the melt 104 is controlled throughout the pulling process.

[0020] The ingot pulling apparatus 100 also includes a reflector 151 (or "heat shield") positioned within the growth chamber 152 above the melt 104 to cover the ingot 113 during ingot growth. The reflector 151 may be partially positioned within the crucible 102 during crystal growth. The reflector 151 defines a central passage 160 for receiving the ingot 113 as it is pulled by the pulling mechanism 114.

[0021] The reflector 151 may be a heat shield adapted to retain heat beneath it and above the melt 104. Other reflector structural designs and materials (e.g., graphite) may be used without limitation. The reflector 151 has a bottom 138 (as best shown in FIG. 2 ), which is separated from the surface of the melt by a distance HR during ingot growth. As the ingot 113 is pulled, the distance HR increases due to consumption of the melt 104.

[0022] An exemplary single crystal silicon ingot 113 produced by the Czochralski process is shown in Figure 4. The ingot 113 includes a neck 116, an outer flaring portion 142 (synonymously "crown" or "cone"), a shoulder 119, and a constant diameter body 145. The neck 116 is attached to a seed crystal 122 that is raised into contact with the melt to form the ingot 113. The body 145 is suspended from the neck 116. The neck 116 terminates when the cone portion 142 of the ingot 113 begins to form.

[0023] The constant diameter portion 145 of the ingot 113 has a peripheral edge 150, a central axis A that is parallel to the peripheral edge 150, and a radius R that extends from the central axis A to the peripheral edge 145. The central axis A also passes through the cone 142 and the neck 116. The diameter of the ingot body 145 may vary, and in some embodiments, the diameter may be about 150 mm, about 200 mm, about 300 mm, greater than about 300 mm, about 450 mm, or greater than about 450 mm.

[0024] The single crystal silicon ingot 113 may generally have any resistivity. The single crystal silicon ingot 113 may be doped or undoped.

[0025] FIG. 4 illustrates an exemplary computing device 400 that may be used as or as part of 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 all of the components shown in FIG. 4 . 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., 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 is exemplary only and is not intended to limit in any way the definition and / or meaning of the term “processor.” Memory 404 stores non-transitory computer-readable instructions for performing the techniques described herein. Such instructions, when executed by processor 402, cause processor 402 to perform at least a portion of the methods described herein. In some embodiments, memory 404 stores computer-readable instructions for providing a user interface to a user via media output component 406 and for receiving and processing input from input device 408.

[0026] 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). While illustrated as separate from processor 402, in some embodiments, memory 404 is combined with processor 402, such as in a microcontroller or microprocessor, but may still be referred to separately. The above memory types are exemplary only and are not limiting as to the types of memory that may be used for storing computer programs. Media output component 406 is configured to present information to a user (e.g., a system operator). Media output component 406 is any component capable of conveying information to a user. In some embodiments, media output component 406 includes an output adapter, such as a video adapter and / or an audio adapter. The output adapter is operably connected to the processor 402 and is operably 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., speakers or headphones).

[0027] Computing device 400 includes or is connected to input device(s) 408 for receiving input from a user. Input device 408 is any device that enables 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. Input device 408 may include, for example, a variable resistor, input dial, keyboard / keypad, pointing device, mouse, stylus, touch-sensitive panel (e.g., touchpad or touchscreen), gyroscope, accelerometer, position detector, audio input device, or any combination thereof. A single component, such as a touchscreen, may function as both an output device for media output component 406 and as an input device 408.

[0028] The communication interface allows the computing device 400 to communicate with remote devices and systems, such as remote sensors, remote databases, remote computing devices, etc., and may include multiple communication interfaces for interacting with multiple remote devices or systems. The communication interface may be a wired or wireless communication interface that allows the computing device 400 to communicate with remote devices and systems directly or via a network. The wireless communication interface may include a radio frequency (RF) transceiver, a Bluetooth® adapter, a Wi-Fi transceiver, a ZigBee® 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, Kirkland, Washington, and ZigBee is a registered trademark of the ZigBee Alliance, San Ramon, California.) The wired communication interface may use any suitable wired communication protocol for direct communication, 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 for communicating with remote devices and systems via the network. The computing systems described herein may include additional, fewer, or alternative functionality. The computing systems discussed may include or be executed via computer-executable instructions stored on one or more non-transitory computer-readable media.

[0029] As shown in Figures 1 and 4, the ingot puller includes a laser system 170 that is used to selectively transmit a laser beam to the peripheral edge 150 of the ingot. As shown in Figure 2, the laser system 170 can be used to increase the power of the beam to heat the ingot edge 150 so as to increase the local temperature gradient at the ingot edge 150. By selectively heating the ingot edge 150 at or near the melt surface 111 (i.e., the melt-ingot interface), defects created in the ingot during the crystal growth process can be controlled. Additionally, the methods and systems described herein allow the side heater 135 to operate at a lower temperature.

[0030] The laser system 170 and controller 172 define an auxiliary heating system. The laser system 170 is used by the controller 172 to direct the laser beam to a position where it will heat the ingot end 150 and to set the power output for the laser system 170. The laser system 170 includes a high-power laser 190 mounted on rails 192 to allow positioning of the laser 190. The laser 190 and rails 192 are located outside the growth chamber 152. The laser 208 is a diode laser with a laser output power ranging from 1 kW to 3 kW, a wavelength of 520 nm, a divergence of less than 0.3, and a beam size of 3 mm, capable of providing focused radiant heat to a target area.

[0031] To use the supplemental heating system, a laser 190 is directed at a region near or adjacent to the interface between the ingot end 150 and the melt surface 111. The laser 190 is controlled to increase the power of the beam to heat the ingot end 150 so as to increase the local temperature gradient at the ingot end. Increasing the local temperature gradient at the ingot end 150 reduces edge band defects in the ingot, as explained in more detail below. The laser 190 can be advanced along a rail 192 so that the beam is selectively directed at a region 10 mm to 20 mm from the ingot end. The rail 192 can be positioned vertically, horizontally, or diagonally. In an alternative embodiment, the laser 190 is mounted on a gimbal or robotic arm to position the laser 190 and adjust where the beam is directed to heat the ingot end 150.

[0032] The laser beam has a first width and a second width, the second width being greater than the first width. The second width heats a larger surface area of ​​the ingot end 150. The width of the beam is adjusted appropriately by varying the focal length of the laser 190. In some embodiments, the second width is 10 mm greater than the first width.

[0033] The width of the laser beam may remain constant and be narrow relative to the first and second widths (referred to as the "spot beam"). The laser 190 may be continuous up and down a cycle distance along rail 192 so that the spot beam distributes a focused, narrow beam across a larger area of ​​ingot end 150 as ingot 113 (of FIG. 1) is pulled and rotated. The cycle of laser 190 produces a sinusoidal beam pattern on ingot 113, the pattern having an amplitude that is half the cycle distance. In some embodiments, the cycle distance is 10 mm. In some embodiments, the cycle distance is 20 mm. In some embodiments, the cycle distance is in the range of 5 mm to 50 mm.

[0034] The ingot can be pulled at a first rate when the laser 190 is not emitting a beam, and the crystalline ingot can be pulled at a second rate using an auxiliary heating system, e.g., a laser beam to heat the ingot edge 150. The second rate is faster than the first rate. By using the auxiliary heating system to heat the ingot edge 150, edge band defects in the ingot are not increased relative to the edge band defects that normally occur at the first rate. In some embodiments, the edge band defects are the same or nearly the same at the first and second rates.

[0035] Similarly, the side heater 135 can be operated at a first temperature when the laser 190 is not emitting a beam at the ingot edge 150, and can be operated at a second, lower temperature when the laser 190 is emitting a beam at the ingot edge 150. Thus, by activating the laser to emit a beam, the side heater 135 can be operated at a lower temperature, which reduces degradation of components within the hot zone and increases the operating life of the side heater 135 while reducing edge band defects in the ingot.

[0036] As shown in FIG. 2 , operating the laser 190 to emit a beam to heat the ingot edge 150 allows the crystal to be pulled with a smaller gap G between the melt surface 111 and the bottom edge 153 of the reflector 151. Because the side heater 135 can be operated at a lower temperature with the laser 190 emitting a beam at 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 cause the reflector 151 to deteriorate due to 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, reducing edge band defects in the ingot as it is pulled.

[0037] Furthermore, by reducing the gap G between the melt surface 111 and the bottom edge 153 of the reflector 151, the cooling rate increases throughout the ingot. Increasing the cooling rate near the triple phase point of the ingot (near the ingot edge 150) is desirable because it allows the ingot to be pulled at a faster rate. Reducing the gap G between the melt surface 111 and the bottom edge 153 of the reflector 151 without activating the laser 190 to emit a beam to heat the ingot edge 150 increases edge band defects in the ingot because the temperature gradient is no longer optimal. Activating the laser 190 reduces the gap G between the melt surface 111 and the bottom edge 153 of the reflector 151, increasing or maintaining the pulling rate while maintaining the temperature gradient within the optimal range.

[0038] Edge band formation is a defect introduced by point defect dynamics in the ingot. To mitigate or control edge band defect formation, the temperature gradient of the three-phase point in the region near or adjacent to the interface between the ingot edge 150 and the melt surface 111 is adjusted. The laser beam controls the temperature gradient in the region heated by the laser beam. As a result, the point defect distribution in the crystalline ingot is changed, and edge band formation is reduced by this process. The process can be further optimized by adjusting the exact location where the beam is illuminated or by changing the width of the laser beam. The power of the beam controls the three-phase point in the region where the beam is directed.

[0039] 1, the controller 172 is connected to the laser 190 and the side heater 135 and is programmed to perform at least the following functions: the laser 208 is controlled to direct a laser beam at the ingot end 150 and is controlled to increase the power of the beam to heat the ingot end 150 so as to increase the local temperature gradient at the ingot end 150. In some embodiments, the controller is further programmed to decrease the power of the side heater 135.

[0040] 5, a laser 290 mounted on a rail 192 directs a beam at a region of the surface melt 111. The laser 290 can be used independently or in combination with the laser 190, which directs a beam at the crystal end 150. The laser 290 directs a laser beam at a first region R1 of the surface melt 111. Similar to the laser 190, the laser 290 selectively increases the temperature of the surface in the first region R1, allowing the side heaters to operate at a lower temperature.

[0041] The laser 290 can be positioned to selectively transmit a beam along the melt surface 111 to a second region 10 mm to 20 mm away from the first region. Further, the beam can be adjusted to have either a first width or a second width, the second width being greater than the first width and 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.

[0042] 6 and 7 illustrate temperature gradients 702-720 (in grayscale) for the melt 104. As shown in FIG. 6, the side heaters 135 are activated to emit a first temperature to the melt 104, and the melt 104 has a substantially constant temperature. As shown in FIG. 7, the temperature gradients 702, 704, 706, 708, 710, 712, 714, 716, 718, and 720 are depicted in order of decreasing temperature. Gradient 702 has a maximum gradient temperature at 1,713.6 degrees Kelvin, and gradient 720 has a minimum gradient temperature at 1,676.6 degrees Kelvin. By directing a beam from the laser 290 toward the surface 111, the surface 111 surrounding the center has a higher local temperature, thereby allowing the side heaters 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, which is further beneficial in increasing seed lift, controlling the crystal diameter, reducing crystal distortion, and controlling the melt-crystal interface shape.

[0043] An exemplary method 300 for controlling edge band defects in a crystalline ingot pulled in a crystal ingot puller is shown in FIG. 8. The method includes step 302 of pulling a crystalline ingot from a melt; step 304 of emitting a high-power laser beam from a laser to an edge of the ingot defined by the outer surface of the ingot contacting the top surface of the melt; and step 306 of increasing the power of the beam to heat the ingot edge to increase a local temperature gradient at the ingot edge, where increasing the local temperature gradient at the ingot edge reduces the edge band defects in the ingot. The method can further include step 308 of decreasing the temperature of a heater from a first temperature to a second temperature, the second temperature being lower than the first temperature, and where the edge band defects in the crystalline ingot at the first heater temperature are the same as the edge band defects in the crystalline ingot at the second temperature.

[0044] 9 includes controlling a surface temperature of a melt in a crucible of a crystal ingot puller, the crystal ingot puller including a heater. The method includes emitting 602 a high-power laser beam from a laser onto 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. The method 600 can further include decreasing 606 the temperature of the heater from a first temperature to a second temperature, the second temperature being lower than the first temperature.

[0045] The embodiments described herein provide the ability to control the three-phase point between the edge of the ingot and the surface of the melt. The embodiments described herein provide an auxiliary heat source in the form of a high-power laser beam directed at the edge of the ingot and the surface of the melt. Another advantage of using the embodiments described herein is the problem associated with premature wear of crystal ingot pulling equipment components due to excessive heat exposure from the side heaters. By using an auxiliary heat source to control the three-phase point between the edge of the ingot and the surface of the melt, the side heaters can operate at lower temperatures while still reducing end failure defects in the crystal ingot. Thus, the crystal ingot pulling equipment components are less exposed to extreme heat.

[0046] When introducing elements of the disclosure or embodiment(s) thereof, the articles "a," "an," "the," and "said" are intended to mean that there are 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 specific orientational terms (e.g., "top," "bottom," "side," "down," "up," etc.) is for convenience of description and does not require a particular orientation of the items being described.

[0047] Because various changes may be made in the structures and methods described above without departing from the scope of the present disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense.

Claims

1. A single crystal ingot pulling apparatus, a crucible for containing the melt; a single crystal ingot at least partially grown from the melt, the ingot having a body defining an outer surface, the outer surface of the ingot contacting an upper surface of the melt defining an ingot end; a heater at least partially surrounding the crucible and the ingot; a laser system for selectively transmitting a laser beam to the edge of the ingot; a controller connected to the laser and the heater for selectively controlling the output of the laser and the heater; Single crystal ingot pulling equipment.

2. The controller controlling the laser to direct the laser beam at an edge of the ingot; programmed to control a laser to increase the power of the beam to heat the ingot edge so as to increase a local temperature gradient at the ingot edge; Increasing the local temperature gradient at the ingot edge reduces edge band defects in the ingot.

2. The single crystal ingot pulling apparatus according to claim 1.

3. the laser is configured to selectively direct the beam to a region 10 mm to 20 mm from the edge of the ingot; 2. The single crystal ingot pulling apparatus according to claim 1.

4. the beam has a first width and a second width, the second width being greater than the first width, the second width heating a larger surface area of ​​the ingot edge; 2. The single crystal ingot pulling apparatus according to claim 1.

5. The second width is 10 mm greater than the first width.

5. The single crystal ingot pulling apparatus according to claim 4.

6. The laser power is in the range of 1 kW to 3 kW.

2. The single crystal ingot pulling apparatus according to claim 1.

7. the ingot is pulled at a first speed when the laser is not emitting the beam, and the crystalline ingot is pulled at a second speed when the laser is emitting the beam at the end of the ingot, the second speed being greater than the first speed; 2. The single crystal ingot pulling apparatus according to claim 1.

8. The edge band defect of the ingot at the first speed is the same as the edge band defect of the ingot at the second speed.

8. The single crystal ingot pulling apparatus according to claim 7.

9. the laser is mounted on a rail for continuously cycling the laser up and down a cycling distance along the rail; 2. The single crystal ingot pulling apparatus according to claim 1.

10. the laser produces a sinusoidal beam pattern on the ingot, the pattern having an amplitude of half the cycle distance; 10. The single crystal ingot pulling apparatus according to claim 9.

11. The cycle distance is in the range of 10 mm to 20 mm.

10. The single crystal ingot pulling apparatus according to claim 9.

12. the controller operates the heater at a first temperature when the laser is not emitting the beam toward the ingot edge, and the controller operates the heater at a second temperature when the laser is emitting the beam toward the ingot edge, the second temperature being lower than the first temperature; 2. The single crystal ingot pulling apparatus according to claim 1.

13. an end band defect at the ingot edge at the first temperature of the heater is the same as an end band defect at the ingot edge at the first temperature; 13. The single crystal ingot pulling apparatus according to claim 12.

14. a bottom end of a reflector disposed within the ingot pulling apparatus 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; 13. The single crystal ingot pulling apparatus according to claim 12.

15. The power of the beam controls three-phase points in the area where the beam is directed.

15. The single crystal ingot pulling apparatus according to claim 14.

16. A single crystal ingot pulling apparatus, a crucible for containing the melt; a heater at least partially surrounding the crucible and the ingot; a laser system that selectively transmits a laser beam to a first region of a surface of the melt; a controller connected to the laser and the heater and configured to selectively control the output of the laser and the heater, the controller comprising: controlling the laser to direct the beam at the first region of the surface of the melt; programmed to control the laser to increase the power of the beam to heat the first region so as to increase the local temperature of the first region; Single crystal ingot pulling equipment.

17. the laser is configured to selectively transmit the beam to a second region 10 mm to 20 mm away from the first region; 17. The single crystal ingot pulling apparatus according to claim 16.

18. the beam has a first width and a second width, the second width being greater than the first width, and the second width being configured to heat a larger surface area of ​​the surface of the melt.

17. The single crystal ingot pulling apparatus according to claim 16.

19. The second width is 10 mm greater than the first width.

19. The single crystal ingot pulling apparatus according to claim 18.

20. The power output is in the range of 1 kW to 3 kW.

17. The single crystal ingot pulling apparatus according to claim 16.

21. the controller operates the heater at a first temperature when the laser is not emitting the beam onto the first region, and the controller operates the heater at a second temperature when the laser is emitting the beam onto the first region, the second temperature being lower than the first temperature; 17. The single crystal ingot pulling apparatus according to claim 16.

22. 1. A method for controlling edge band defects in a crystalline ingot pulled in a crystalline ingot puller, the crystalline ingot puller including a crucible for containing a melt and a heater, the heater being operated at a first temperature, the method comprising: Pulling the crystalline ingot from the melt; emitting a high-power laser beam from the laser at an end of the ingot defined by an outer surface of the ingot contacting an upper surface of the melt; increasing the power of the beam to heat the ingot end so as to increase the local temperature gradient at the ingot end; Increasing the local temperature gradient at the ingot edge reduces edge band defects in the ingot. method.

23. and 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, and the edge band defects of the crystalline ingot at the first temperature of the heater being the same as the edge band defects of the crystalline ingot at the first temperature.

23. The method of claim 22.

24. 1. A method for controlling a surface temperature of a melt in a crucible of a crystal ingot puller, the crystal ingot puller including a heater, the heater being operated at a first temperature, the method comprising: emitting a high power laser beam from a laser onto a surface region of the melt; increasing the power of the beam to heat a region of the surface of the melt to increase a local temperature gradient at the ingot end of the ingot; Increasing the local temperature gradient at the ingot edge reduces edge band defects in the ingot. method.

25. further comprising decreasing the temperature of the heater from the first temperature to a second temperature, the second temperature being lower than the first temperature.

25. The method of claim 24.

26. and pulling the ingot at a second speed while the laser is emitting the beam at the end of the ingot, the second speed being greater than the first speed when the laser is not emitting the beam.

25. The method of claim 24.

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