CVD-Siemens Reactor Process Hydrogen Recycle System
First Claim
Patent Images
1. In a CVD-Siemens system including a reactor vessel containing at least one reaction chamber surrounded by a jacket, wherein a pre-heating fluid is circulated in the jacket;
- one or more electrode assemblies extending into the reaction chamber wherein each electrode assembly comprises a gas inlet, one or more heat transfer fluid inlets/outlets;
at least one pair of silicon filaments, the filaments connected to each other at their upper ends with a silicon bridge to form a filament/slim rod assembly, each filament/slim rod assembly enclosed in an isolation jacket;
a source of a silicon-bearing gas connected to the interior of the vessel for supplying the gas into the reaction chamber, wherein the reaction chamber includes one or more distributor locations, to produce a reaction and to deposit polycrystalline silicon on the filaments by chemical vapor deposition thereby producing a rod of polycrystalline silicon;
a heat transfer system connected to the jacketed reaction chamber to supply heat transfer fluid to preheat the filaments/slim rod assemblies; and
a power supply, the improvement comprising a hydrogen recovery and recycle system comprising;
a liquid Nitrogen cooling system;
a silane condenser;
a recycle hydrogen cooler; and
a Hydrogen regeneration cooler, a compressor, and one or more interchangers wherein the discharged gas from the reactor is cooled to between about 30 and 40°
C., the compressor accepts and compresses the cooled gas to the system requirement pressure, the interchangers cool an off-gas to between −
160 and −
165°
C. using counter flow between cooler and warmer streams, the off-gas stream is further cooled to between −
170 and −
180°
C. using a liquid nitrogen exchanger in the hydrogen regeneration cooler.
1 Assignment
0 Petitions
Accused Products
Abstract
A hydrogen recycle process and system for use with chemical vapor deposition (CVD) Siemens type processes is provided. The process results in substantially complete or complete hydrogen utilization and substantially contamination-free or contamination-free hydrogen.
42 Citations
9 Claims
-
1. In a CVD-Siemens system including a reactor vessel containing at least one reaction chamber surrounded by a jacket, wherein a pre-heating fluid is circulated in the jacket;
- one or more electrode assemblies extending into the reaction chamber wherein each electrode assembly comprises a gas inlet, one or more heat transfer fluid inlets/outlets;
at least one pair of silicon filaments, the filaments connected to each other at their upper ends with a silicon bridge to form a filament/slim rod assembly, each filament/slim rod assembly enclosed in an isolation jacket;
a source of a silicon-bearing gas connected to the interior of the vessel for supplying the gas into the reaction chamber, wherein the reaction chamber includes one or more distributor locations, to produce a reaction and to deposit polycrystalline silicon on the filaments by chemical vapor deposition thereby producing a rod of polycrystalline silicon;
a heat transfer system connected to the jacketed reaction chamber to supply heat transfer fluid to preheat the filaments/slim rod assemblies; and
a power supply, the improvement comprising a hydrogen recovery and recycle system comprising;
a liquid Nitrogen cooling system;
a silane condenser;
a recycle hydrogen cooler; and
a Hydrogen regeneration cooler, a compressor, and one or more interchangers wherein the discharged gas from the reactor is cooled to between about 30 and 40°
C., the compressor accepts and compresses the cooled gas to the system requirement pressure, the interchangers cool an off-gas to between −
160 and −
165°
C. using counter flow between cooler and warmer streams, the off-gas stream is further cooled to between −
170 and −
180°
C. using a liquid nitrogen exchanger in the hydrogen regeneration cooler. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- one or more electrode assemblies extending into the reaction chamber wherein each electrode assembly comprises a gas inlet, one or more heat transfer fluid inlets/outlets;
-
9. A method for recovery, purification and recycle of hydrogen in a CVD Siemens process comprising:
-
collecting off gases from a CVD Siemens process reactor; cooling the off gases; filtering the off gases; compressing the off gases to at least about 25 psig; cooling the compressed off gases to a temperature between about −
160 C and −
165 C and then cooling the compressed off gases againt to a temperature between about −
170 C and −
180 C thereby separating condensed impurities from a hydrogen component of the off gases;passing the hydrogen component through absorption beds to remove any argon, hydrocarbons, uncondensed silanes, boron and phosphorous compounds from the hydrogen component to obtain a first filtered hydrogen stream; cryogenically filtering the first filtered hydrogen stream to produce a second filtered hydrogen stream; heating the second filtered hydrogen stream to between about 25 C and 30 C to produce a high purity hydrogen stream; passing the high purity hydrogen stream through a recycle hydrogen filter to remove particles having a size between 0.1 and 0.4 microns to produce a final hydrogen recycle stream; and recycling the final hydrogen recycle stream to the CVD Siemens process reactor.
-
Specification