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US 5,798,137 AGranted
Method for silicon deposition
AssigneeAdvanced Silicon Materials LLC
InventorsStephen M. Lord, Robert J. Milligan
Life of this patent
Estimating the term…
Abstract
Silicon beads are produced by chemical vapor deposition (CVD) on seed particles generated internal to a CVD reactor. The reactor has multiple zones, including an inlet zone where beads are maintained in a submerged spouted bed and an upper zone where beads are maintained in a bubbling fluidized bed. A tapered portion of the upper zone segregates beads by size. Systems for inspecting, sorting and transporting product beads are also disclosed.
Claims35
A process for the deposition of silicon on particles that are located inside a vessel, the process comprising:
- providing a reactor having a vessel, which vessel has a wall which defines a chamber having at least two zones including (a) an inlet zone and (b) an upper zone that communicates with and is located above the inlet zone to receive gas moving upwardly from the inlet zone, and which vessel has a fluidizing inlet for delivering gas into the inlet zone;
- injecting a silicon-bearing gas through the fluidizing inlet to provide a fluidizing jet in the chamber without passing the gas through a distribution plate so as to maintain particles in the inlet zone in a submerged spouted bed;
- maintaining particles in the inlet zone at an operating temperature sufficient to cause silicon to deposit from the silicon-bearing gas onto particles in the inlet zone;
- and
- maintaining particles in the upper zone in a bubbling fluidized bed.
2 more elements
A process for the deposition of silicon on particles that are located inside a vessel, the process comprising:
- providing a reactor having a vessel, which vessel has a wall which defines a chamber having at least two zones including (a) an inlet zone and (b) an upper zone which communicates with and is located above the inlet zone to receive gas moving upwardly from the inlet zone, and which vessel has a fluidizing inlet for delivering gas into the inlet zone;
- injecting a silicon-bearing gas through the fluidizing inlet to provide a fluidizing jet of sufficient velocity to (a) maintain particles in the inlet zone in a submerged spouted bed, (b) cause particles to impact each other in the inlet zone such that grinding of particles occurs to form ground particles of sufficiently small size that the ground particles serve as seed particles to receive silicon deposited from the silicon-bearing gas, and (c) maintain particles in the inlet zone oriented in the position of maximum drag relative to the gas flow;
- maintaining particles in the inlet zone at an operating temperature sufficient to cause silicon to deposit from the silicon-bearing gas onto particles in the inlet zone;
- and
- maintaining particles in the upper zone in a bubbling fluidized bed.
2 more elements
A process for the deposition of silicon on particles that are located inside a vessel, the process comprising:
- providing a reactor having a vessel, which vessel has a wall which defines a chamber having at least two zones including (a) an inlet zone and (b) an upper zone which communicates with and is located above the inlet zone to receive gas moving upwardly from the inlet zone, and which vessel has a fluidizing inlet for delivering gas into the inlet zone;
- injecting a silicon-bearing gas through the fluidizing inlet to provide a fluidizing jet at a size, shape, and velocity sufficient to (a) maintain particles in the inlet zone in a submerged spouted bed, (b) cause particles to impact each other in the inlet zone such that grinding of particles occurs to form ground particles of sufficiently small size that the ground particles serve as seed particles to receive silicon deposited from the silicon-bearing gas, and (c) maintain particles in the inlet zone in a position indicated by the particle Reynolds number range of 5.5 to 200;
- maintaining particles in the inlet zone at an operating temperature sufficient to cause silicon to deposit from the silicon-bearing gas onto particles in the inlet zone;
- and
- maintaining particles in the upper zone in a bubbling fluidized bed.
2 more elements
A process for the deposition of silicon on particles that are located inside a vessel, the process comprising:
- providing a reactor having a vessel, which vessel has a wall which defines a chamber having at least two zones including (a) an inlet zone and (b) an upper zone which communicates with and is located above the inlet zone to receive gas moving upwardly from the inlet zone, and which vessel has a fluidizing inlet for delivering gas into the inlet zone;
- injecting a silicon-bearing gas through the fluidizing inlet to provide a fluidizing jet;
- maintaining particles in the inlet zone at an operating temperature sufficient to cause silicon to deposit from the silicon-bearing gas onto particles in the inlet zone;
- maintaining particles in the upper zone in a bubbling fluidized bed;
- and
- injecting a halogen-containing gas into a region of the inlet zone that contains the jet to keep the vessel wall etched in the region of the jet, to increase the particle Reynolds number, and to heat the region of the jet by energy released from an exothermic reaction of the halogen-containing gas with a fraction of silicon-containing species at the region of the jet, the amount of energy produced by the reaction being sufficient to heat the particles in the jet.
3 more elements
A process for the deposition of silicon on a substrate located inside a vessel that has an inlet for the injection of a silicon-bearing gas, the process comprising:
- providing a reactor system including a vessel having a wall with an interior surface which defines a chamber and an inlet for the injection of a silicon-bearing gas;
- providing a slip coating on at least a portion of the interior surface of the wall to inhibit adherence of silicon deposits to the wall;
- providing a layer of silicon on the slip coating, the slip coating being a powder having a melting point in Kelvin that is more than twice the temperature, also in Kelvin, of the layer of silicon during operation of the reactor system;
- injecting a silicon-bearing gas through the inlet into the chamber to provide a fluidizing jet in the chamber without passing the gas through a distribution plate;
- and
- heating at least some of the contents of the chamber to promote the deposition of silicon on a substrate.
3 more elements
A process for the deposition of silicon on particles that are located inside a vessel that has an inlet for the injection of a silicon-bearing gas to fluidize the particles, the process comprising:
- prior to the injection of the silicon-bearing gas, removing any oxygen-containing contaminants from the vessel by reacting a halogen-containing gas with the contaminants under conditions that favor formation of solid particles and that disfavor deposition of contaminant films on the particles or the vessel;
- and
- injecting the silicon-bearing gas through the inlet so as to maintain particles in a fluidized bed and to deposit silicon on the particles.
A process for the deposition of silicon on particles that are located inside a vessel that has an inlet for the injection of a silicon-bearing gas to fluidize the particles and that has an outlet in communication with a particle withdrawal passageway defined by the interior surface of a particle withdrawal tube, the process comprising:
- injecting a silicon-bearing gas through the inlet to provide a fluidizing jet in the vessel without passing the gas through a distribution plate so as to maintain particles in a fluidized bed and to deposit silicon on the particles;
- removing particles, on which silicon has been deposited, from the vessel through the passageway;
- providing a layer of silicon on the inner surface of the particle withdrawal tube;
- and
- maintaining the thickness of the layer in a predetermined range by flowing a silicon-bearing gas or etchant through the passageway as needed to maintain equilibrium between etching and silicon deposition.
2 more elements
A process for the deposition of silicon on particles that are located inside a vessel that has an inlet for the injection of a silicon-bearing gas to fluidize the particles and that has an outlet in communication with a particle withdrawal passageway defined by the interior surface of a particle withdrawal tube, the process comprising:
- injecting a silicon-bearing gas through the inlet so as to maintain particles in a fluidized bed and to deposit silicon on the particles;
- removing particles, on which silicon has been deposited, from the vessel through the passageway;
- providing a layer of silicon on the inner surface of the particle withdrawal tube;
- and
- maintaining the thickness of the layer in a predetermined range by flowing a silicon-bearing gas or etchant through the passageway, concurrently with the removing and countercurrent to the particles, as needed to maintain equilibrium between etching and silicon deposition.
2 more elements
A process for the deposition of silicon on particles that are located inside a vessel, the process comprising:
- providing a reactor system having a vessel, which vessel has a wall which defines a chamber having at least two zones including (a) an inlet zone, and (b) an upper zone that communicates with and is located above the inlet zone to receive gas moving upwardly from the inlet zone, and which vessel has a fluidizing inlet for delivering gas into the inlet zone and an outlet in communication with a particle withdrawal passageway defined by the interior surface of a particle withdrawal tube;
- providing a plurality of silicon particles inside the chamber;
- providing a silicon-bearing gas and a diluent gas;
- injecting the silicon-bearing gas through the fluidizing inlet to provide a fluidizing jet of sufficient velocity to maintain particles in the inlet zone in a submerged spouted bed and to circulate the particles inside the vessel and cause particles to impact each other in the inlet zone such that grinding of particles occurs in the inlet zone to form ground particles of sufficiently small size that the ground particles serve as seed particles to receive silicon deposited from the silicon-bearing gas;
- injecting the diluent gas into the vessel;
- prior to injecting the diluent gas, removing any oxygen containing contaminants from the diluent gas by (a) reacting a silicon-bearing gas with the contaminants under conditions that favor formation of solid particles, and (b) filtering the resulting solid particles from the diluent gas at a location outside the chamber;
- controlling the amount of grinding by adjusting at least one parameter selected from the group consisting of orifice diameter of the fluidizing inlet, composition of the silicon-bearing gas, mass flow of the silicon-bearing gas, pressure, and temperature to alter the kinetic power of the jet;
- maintaining the particles inside the chamber at an operating temperature of at least 500.degree. C. sufficient to cause silicon to deposit from the silicon-bearing gas onto the particles and on the wall of the vessel;
- producing a supplemental jet of gas in the vessel at a location above the fluidizing inlet, the supplemental jet being sized and positioned to increase the frequency of particle impacts and provide additional grinding of particles propelled by the supplemental jet;
- circulating a fraction of any fine silicon particles that are produced inside the vessel into the fluidizing jet so that the fine particles are increased in average size by heterogeneous silicon deposition and so that homogeneous nucleation of amorphous silicon particles from the silicon-bearing gas is suppressed;
- conducting the injecting of the silicon-bearing gas under conditions such that, in at least a portion of the chamber, particles are inherently oriented in the position of maximum drag relative to the gas flow, which position is indicated by the particle Reynolds number range of 5.5 to 200;
- maintaining particles in the upper zone in a bubbling fluidized bed and at a temperature such that the bed acts as a granular filtration device to trap silicon powder that enters the bed;
- injecting a halogen-containing gas into the vessel to convert any silicon powder and any unreacted silicon-bearing gas to halogenated species at temperatures and pressures sufficient to inhibit the deposition of silicon or silicon halide polymers on piping and equipment which receive effluent gas from the chamber;
- prior to injecting the halogen-containing gas, removing any oxygen-containing contaminants from the halogen-containing gas by (a) reacting a silicon-bearing gas with the contaminants under conditions that favor formation of solid particles, and (b) filtering the resulting solid particles from the halogen-containing gas at a location outside the chamber;
- holding particles in the inlet zone at a temperature of 700.degree. C. to 1200.degree. C., during deposition of silicon on the particles, to reduce the hydrogen content of the particles and promote polycrystalline structure in the particles;
- holding particles in the upper zone at a temperature of 700.degree. C. to 1200.degree. C. for 1 to 24 hours to reduce the hydrogen content of the particles and promote polycrystalline structure in the particles;
- and
- removing particles, on which silicon has been deposited, from the vessel through the particle withdrawal passageway.
15 more elements
A process for the deposition of silicon on particles that are located inside a vessel, the process comprising:
- providing a vessel having a wall which defines a chamber and a fluidizing inlet for delivering gas into the chamber;
- and
- injecting a silicon-bearing gas through the fluidizing inlet in such a manner as to both (a) deposit silicon on particles in the chamber and (b) provide a fluidizing jet in the chamber without passing the gas through a distribution plate, which jet contacts the particles so as to circulate the particles in the chamber, the gas being injected with sufficient energy to grind particles in the chamber and to break off particles of sufficiently small size that the broken off particles can serve as seed particles to receive silicon deposited from the silicon-bearing gas.
A process for the deposition of silicon on particles that are located inside a vessel, the process comprising:
- providing a vessel having a wall which defines a chamber and a fluidizing inlet for delivering gas into the chamber;
- and
- injecting a silicon-bearing gas through the fluidizing inlet under conditions such that (a) particles in the chamber are maintained in a fluidized bed, (b) silicon is deposited on the particles, and (c) seed particles are inherently oriented in the position of maximum drag relative to the gas flow, which position is indicated by the particle Reynolds number range of 5.5 to 200.
A process for the deposition of silicon on particles that are located inside a vessel, the process comprising:
- providing a vessel having a wall which defines a chamber and a fluidizing inlet for delivering gas into the chamber;
- and
- injecting a silicon-bearing gas through the fluidizing inlet at conditions such that (a) particles in the chamber are maintained in a fluidized bed, (b) silicon is deposited on the particles, and (c) at least a portion of the bed is maintained at a voidage between 0.35 and 0.55 in a zone having a negative velocity profile.
A process for the deposition of silicon on particles that are located inside a vessel, the process comprising:
- providing a vessel having a wall which defines a chamber and a fluidizing inlet for delivering gas into the inlet zone;
- injecting a silicon-bearing gas through the fluidizing inlet to provide a fluidizing jet in the chamber without passing the gas through a distribution plate so as to maintain particles in the chamber in a fluidized bed and deposit silicon on the particles;
- and
- prior to allowing the wall of the vessel to cool by more than 100.degree. C., at least partially removing deposited silicon from the wall by etching at or near the operating temperature using a halogen-containing gaseous etchant.
1 more element
A process for the deposition of silicon on particles that are located inside a vessel, the process comprising:
- providing a vessel having a wall which defines a chamber and a fluidizing inlet for delivering gas into the chamber;
- injecting a silicon-bearing gas through the fluidizing inlet in such a manner as to both (a) thermally decompose the silicon-bearing gas in the chamber such that silicon is deposited on particles in the chamber and (b) provide a fluidizing jet in the chamber without passing the gas through a distribution plate, which jet contacts the particles so as to circulate the particles in the chamber;
- and
- while the silicon is being deposited on the particles, holding the particles in the chamber at a temperature of 700.degree. C. to 1200.degree. C. to remove hydrogen from the silicon deposited on the particles and to promote polycrystalline structure in the silicon deposited on the particles.
1 more element
A process for the deposition of silicon on particles that are located inside a vessel, the process comprising:
- providing a vessel having a wall which defines a chamber and a fluidizing inlet for delivering gas into the chamber, and having a gas delivery tube which defines a gas inlet passageway that is in communication with the fluidizing inlet;
- injecting a silicon-bearing gas through the fluidizing inlet to provide a fluidizing jet in the chamber without passing the gas through a distribution plate so as to maintain particles in the chamber in a fluidized bed and deposit silicon on the particles;
- heating material inside the chamber by directing radiant energy from a source of radiant energy, via the gas delivery tube, and to a location inside the chamber;
- and
- maintaining the wavelength distribution of the radiant energy such that energy absorbed by silicon-bearing gas inside the chamber is insufficient to cause decomposition of that gas and such that any residual energy is absorbed by the particles.
2 more elements
A process for the deposition of silicon on particles that are located inside a vessel, the process comprising:
- providing a vessel having a wall which defines a chamber, a portion of which is an inlet zone, and which defines a fluidizing inlet for delivering gas into the inlet zone;
- injecting a silicon-bearing gas through the fluidizing inlet so as to maintain particles in the chamber in a fluidized bed and deposit silicon on the particles;
- and
- injecting a halogen-containing gas into the inlet zone to heat a region of the inlet zone by energy released from an exothermic reaction of the halogen-containing gas with a fraction of silicon-containing species in the inlet zone, the amount of energy produced by the reaction being sufficient to heat particles in the inlet zone.
1 more element
A process for the deposition of silicon on particles that are located inside a vessel, the process comprising:
- providing a vessel having a wall which defines a chamber, a fluidizing inlet for delivering gas into the chamber, and a supplemental inlet to deliver gas into the chamber at a location above the fluidizing inlet;
- injecting a silicon-bearing gas through the fluidizing inlet to provide a fluidizing jet in the chamber without passing the gas through a distribution plate so as to maintain particles in the chamber in a fluidized bed to circulate the particles in the chamber;
- and
- injecting a gas through the supplemental inlet in such a manner that grinding of particles occurs in the chamber and ground particles of sufficiently small size are formed to serve as seed particles on which silicon is deposited.
1 more element
Dependencies are inferred from the claim text.