Seed chuck assemblies and crystal pulling systems for reducing deposit build-up during crystal growth process
View Patent ↗Crystal pulling systems for growing monocrystalline ingots from a melt of semiconductor or solar-grade material are described. The crystal pulling systems include seed chuck assemblies designed to reduce formation of deposits on components of the crystal pulling systems by reducing and inhibiting the formation of gas flow recirculation cells within the crystal pulling systems.
1. A crystal pulling system for growing a monocrystalline ingot from a melt of semiconductor or solar-grade material, the system comprising:
a crucible for containing the melt of semiconductor or solar-grade material;
a pulling mechanism configured to pull the ingot from the melt; and
a seed chuck assembly connected to the pulling mechanism, the seed chuck assembly including:
a main body; and
a flow guide directly connected to and disposed radially outward from the main body such that a flow passage is defined between the flow guide and the main body, the flow guide having an outlet through which gas is discharged from the flow passage directly into a space that extends vertically between the melt and the flow guide, the flow passage directing gas downward toward the surface of the melt, the seed chuck assembly being configured to, at the outlet of the flow passage, direct gas downward toward the surface of the melt without directing gas radially outward, the flow guide including a cylindrical constant diameter mid-portion, a lower conical portion extending downward and radially inward from the mid-portion, and an upper conical portion extending upward and radially inward from the cylindrical portion.
2. The crystal pulling system of claim 1 , wherein the lower portion has a thickness less than a thickness of the mid-portion.
3. The crystal pulling system of claim 1 , wherein the flow guide is shaped such that gas flowing through the flow path flows along the main body of the seed chuck assembly.
4. The crystal pulling system of claim 3 , wherein the outer profile of the main body extends radially outward from a first end of the main body to a mid-portion of the main body, and extends radially inward from the mid-portion of the main body to a second end of the main body opposite the first end.
5. The crystal pulling system of claim 1 , wherein the flow guide is constructed from at least one of graphite and quartz.
6. The crystal pulling system of claim 1 , further comprising a vertically-extending baffle disposed within the growth chamber and having an inner diameter defining a central passage for receiving the ingot as the ingot is pulled by the pulling mechanism.
7. The crystal pulling system of claim 6 , wherein the flow guide defines an outer diameter of the seed chuck assembly, and wherein a ratio between the outer diameter of the seed chuck assembly and the inner diameter of the baffle is at least 0.6 and less than 1.0.
8. The crystal pulling system of claim 7 , wherein the vertically-extending baffle is a cooling jacket.
9. A crystal pulling system for growing a monocrystalline ingot from a melt of semiconductor or solar-grade material, the system comprising:
a crucible for containing the melt of semiconductor or solar-grade material;
a pulling mechanism configured to pull the ingot from the melt; and
a seed chuck assembly connected to the pulling mechanism, the seed chuck assembly including:
a main body; and
a flow guide directly connected to and disposed radially outward from the main body such that a flow passage is defined between the flow guide and the main body, the flow guide having an outlet through which gas is discharged from the flow passage, the flow passage directing gas downward toward the surface of the melt, the system being free of structures in a region that extends vertically between the outlet of the flow guide and the surface of the melt, the flow guide including a cylindrical constant diameter mid-portion, a lower conical portion extending downward and radially inward from the mid-portion, and an upper conical portion extending upward and radially inward from the cylindrical portion.
10. A crystal pulling system for growing a monocrystalline ingot from a melt of semiconductor or solar-grade material, the system comprising:
a crucible for containing the melt of semiconductor or solar-grade material;
a pulling mechanism configured to pull the ingot from the melt; and
a seed chuck assembly connected to the pulling mechanism, the seed chuck assembly including:
a main body; and
a flow guide directly connected to and disposed radially outward from the main body such that a flow passage is defined between the flow guide and the main body, the flow guide having an outlet through which gas is discharged from the flow passage, the flow passage directing gas downward toward the surface of the melt, the seed chuck assembly being configured to, at the outlet of the flow passage, direct gas downward toward the surface of the melt without directing gas radially outward, a portion of the flow guide being vertically higher than the main body, the flow guide including a cylindrical constant diameter mid-portion, a lower conical portion extending downward and radially inward from the mid-portion, and an upper conical portion extending upward and radially inward from the cylindrical portion.
11. The crystal pulling system of claim 1 , further comprising a seed crystal disposed and connected to the main body of the seed chuck assembly, wherein at least a portion of the seed crystal is vertically lower than the flow guide.
12. The crystal pulling system of claim 1 , wherein a portion of the main body is vertically lower than the flow guide.
13. The crystal pulling system of claim 1 , wherein the seed chuck assembly includes a plurality of circumferentially-spaced arms that extend from the main body radially outward to the flow guide to connect the flow guide to the main body.
14. The crystal pulling system of claim 9 , further comprising a seed crystal disposed and connected to the main body of the seed chuck assembly, wherein at least a portion of the seed crystal is vertically lower than the flow guide.
15. The crystal pulling system of claim 9 , wherein a portion of the main body is vertically lower than the flow guide.
16. The crystal pulling system of claim 9 , wherein the seed chuck assembly includes a plurality of circumferentially-spaced arms that extend from the main body radially outward to the flow guide to connect the flow guide to the main body.
17. The crystal pulling system of claim 10 , further comprising a seed crystal disposed and connected to the main body of the seed chuck assembly, wherein at least a portion of the seed crystal is vertically lower than the flow guide.
18. The crystal pulling system of claim 10 , wherein a portion of the main body is vertically lower than the flow guide.
19. The crystal pulling system of claim 10 , wherein the seed chuck assembly includes a plurality of circumferentially-spaced arms that extend from the main body radially outward to the flow guide to connect the flow guide to the main body.