What is claimed is:
1. A fuel cell generator comprising:
solid oxide electrolyte fuel cell stacks acting on pressurized hydrogen and carbon monoxide-containing fuel and pressurized oxygen-containing oxidant to provide electrical energy, in which the stacks have positive and negative terminals;
a stack energy dissipater which operates on amplitude proportioning of a resistance load, comprising an electrical resistance load, said load comprising an array of at least two cooled, electrically connected resistors controlled by a voltage-sensitive multi-settable point relay, where individual switching contactors allowing for variable resistance loads are disposed between the array and a circuit breaker; and
where the circuit breaker is in electrical contact with the positive terminal and each of the resistors in the array is in electrical contact with the negative terminal, so that the energy dissipater can draw current, in order to consume hydrogen and carbon monoxide-containing fuel stored within the generator during a transient operation.
2. The fuel cell generator of claim 1, wherein the fuel cell stacks comprise a plurality of tubular solid oxide fuel cells having an inner air electrode in contact with the oxygen-containing gas, an outer fuel electrode in contact with the hydrogen-containing fuel, and an open end extending into a combustion zone in flow communication with the oxygen-containing gas and the hydrogen containing fuel.
3. The fuel cell generator of claim 1, wherein the generator comprises a combustion zone in flow communication with the hydrogen-containing fuel and the oxygen-containing gas, and the means for drawing current from the generator substantially prevents a buildup of heat in the combustion zone after the generator shuts down.
4. The fuel cell generator of claim 3, wherein an operating temperature in the combustion zone is from about 850 C. to about 1,000 C., and the temperature in the combustion zone does not increase by more than about 30 C. after the generator shuts down.
5. The fuel cell generator of claim 1, wherein the chemical energy of the hydrogen containing fuel remaining within the fuel cell stacks and porous insulation surrounding the stacks is converted to electrical energy and dissipated as heat in the array of resistors, instead of by burning with oxidant in the generator.
6. The fuel cell generator of claim 1, wherein the resistors are connected in parallel, and series, where at least one resistor operates in series relationship and the individual contactors switch the resistors.
7. The fuel cell generator of claim 1, wherein the energy dissipater also contains an enabling relay to receive a signal from a control system and shutdown circuits, disabling the switching contactors until such a signal is received.
8. The fuel cell generator of claim 1, wherein the energy dissipater also contains a timing relay to permit some minimum amount of time for energy dissipation, regardless of the voltage level at initiation of the dissipater.
9. The fuel cell generator of claim 1, wherein the circuit breaker is a latching trip breaker effective to disconnect the load when a specified minimum voltage is detected.
10. The fuel cell generator of claim 1, wherein the fuel and oxidant are pressurized to over 151.6 kPa.
11. The fuel cell generator of claim 1,
wherein the fuel and oxidant are pressurized to between 151.6 kPa and 1013 kPa.
12. The fuel cell generator of claim 1, wherein the array of electrically connected resistors contains at least three resistors.
13. A method of dissipating energy during shutdown of a fuel cell generator comprising:
converting pressurized hydrogen and carbon monoxide-containing fuel and pressurized oxygen-containing oxidant to electrical energy in a fuel cell generator;
shutting down the fuel cell generator; and
drawing current from the fuel cell generator after the generator shuts down, thereby to consume at least a portion of the hydrogen and carbon monoxide-containing fuel remaining in the generator and to convert the fuel to oxidized products, thereby to substantially prevent overheating of the generator,
wherein the fuel cell generator contains solid oxide electrolyte fuel cell stacks having positive and negative terminals, where a stack energy dissipater which operates on amplitude proportioning of a resistance load is effective to draw current from the fuel cell generator after shutdown by means of an array of at least two electrical resistors providing a load which is electrically connected to the negative terminal at two or more locations, where the electrical resistors are also electrically connected through individual switching contactors and an associated voltage sensitive multi-settable point relay to a circuit breaker, which circuit breaker is electrically connected to the positive terminal at two or more locations, and where the fuel and the oxidant are pressurized to over 151.6 kPa.
14. The method of claim 13, wherein the chemical energy of the hydrogen and carbon monoxide containing fuel remaining within the fuel cell stacks and porous insulation surrounding the stacks is converted to electrical energy and dissipated as heat in the array of resistors, instead of by burning with oxidant in the generator.
15. The method of claim 13, wherein the fuel cell stacks comprise a plurality of tubular solid oxide fuel cells having an inner air electrode in contact with the oxygen-containing gas, an outer fuel electrode in contact with the hydrogen-containing fuel, and an open end extending into a combustion zone in flow communication with the oxygen-containing gas and the hydrogen containing fuel.
16. The method of claim 13, wherein the fuel and oxidant are pressurized to between 151.6 kPa and 1013 kPa.
17. The method of claim 13, wherein the resistors are connected in parallel and series, where at least one resistor operates in series relationship.
18. The method of claim 13, wherein the array of electrical resistors contains at least three resistors.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A semiconductor device comprising:
a substrate having a single crystalline state;
an insulation structure formed on the substrate, the insulation structure having an opening that partially exposes the substrate;
a plug formed in the opening, the plug including a material in a single crystalline state that is transformed from an amorphous state by an irradiation of a laser beam; and
a channel structure extending upwardly from the plug, the channel structure having a substantially vertical sidewall, the channel structure including a material in a single crystalline state that is transformed from an amorphous state by the irradiation of the laser beam.
2. The semiconductor device of claim 1, wherein the substrate comprises at least one selected from the group consisting of silicon and germanium.
3. The semiconductor device of claim 1, wherein the insulation structure comprises at least one selected from the group consisting of an oxide pattern and a nitride pattern.
4. The semiconductor device of claim 1, wherein the channel structure is doped with an impurity comprising any one selected from the group consisting of boron, phosphorus and arsenic.
5. A method of manufacturing a semiconductor device, the method comprising:
forming a preliminary insulation structure having an opening that partially exposes a substrate, the preliminary insulation structure including at least two patterns of materials that have etching selectivities with respect to one another;
forming an amorphous material structure on the substrate that fills the opening;
transforming the amorphous material structure into a single crystalline material structure by irradiating a laser beam onto the amorphous material structure; and
exposing an upper portion of the single crystalline material structure by removing an uppermost pattern of the preliminary insulation structure to provide an insulation structure, the upper portion of the single crystalline material structure being a channel structure having a substantially vertical sidewall.
6. The method of claim 5, wherein the substrate comprises at least one selected from the group consisting of silicon and germanium.
7. The method of claim 5, wherein the preliminary insulation structure comprises a first insulating pattern, a second insulating pattern and a third insulating pattern that are successively formed.
8. The method of claim 7, wherein the first and the third insulating patterns comprise oxide and the second insulating pattern comprises nitride.
9. The method of claim 5, wherein the opening of the preliminary insulation structure is formed by an anisotropic etching process such that the opening has a substantially vertical sidewall.
10. The method of claim 5, wherein the amorphous material structure is formed by a selective epitaxial growth process.
11. The method of claim 5, wherein the amorphous material structure comprises at least one selected from the group consisting of silicon and germanium.
12. The method of claim 5, wherein the amorphous material structure comprises an impurity.
13. The method of claim 12, wherein the impurity comprises any one selected from the group consisting of boron, phosphorus and arsenic.
14. The method of claim 12, wherein the impurity is doped into the amorphous material structure by a diffusion process while the amorphous material structure is formed.
15. The method of claim 12, wherein the impurity is doped into the amorphous material structure by an ion implantation process after the amorphous material structure is formed.
16. The method of claim 5, wherein the laser beam irradiated onto the amorphous material structure heats the amorphous material structure to a temperature that is a substantial melting point of the amorphous material structure.
17. The method of claim 16 wherein, following removal of the laser beam irradiation, the amorphous material structure, in a molten state, re-solidifies during cooling, to be transformed into the single-crystalline material structure using the substrate as a seed for crystallization.
18. The method of claim 17 wherein the substrate comprises a single-crystal material in a single-crystalline state.
19. The method of claim 5, wherein forming the amorphous material structure comprises:
forming a preliminary amorphous material structure on the substrate and the preliminary insulation structure to fill the opening; and
performing a planarizing process on the preliminary amorphous material structure until the preliminary insulation structure is exposed to form the amorphous material structure confined in the opening.
20. The method of claim 1 wherein the substrate comprises a single-crystal material in a single-crystalline state.