Abstract: Method of determining contaminants in a semiconductor processing apparatus in which a high purity, high carrier lifetime semiconductor test wafer is processed and the degradation of its carrier lifetime is determined.

Abstract: A method of annealing a wafer in a rapid thermal annealer is disclosed. The walls of the chamber are heated more rapidly than is the wafer. In a preferred embodiment, the interior of the graphite walls of the annealer is lined with a molybdenum sheet which is open toward the lamps that heat the chamber. Thus, the walls heat very rapidly to a temperature greater than the condensation point of arsenic, preventing arsenic condensation on the walls. Effective annealing can be achieved at wall temperatures in the range of 500.degree. to 600.degree. C. Prior to the heat ramp up, an arsenic atmosphere, preferably trimethylarsenic (TMAs) at an appropriate overpressure is introduced. This overpressure is maintained both during the heating and cooling cycle. By the use of this method, the exposure time for annealing can be reduced from prior times of as much as 20 minutes to as little as 10 seconds.

Abstract: A method for processing solar cells, and particularly thin solar cells is disclosed. The method contemplates processing the front surface of the cell on a wafer of normal thickness. A transparent substrate is adhered to the front of the processed cell. The bulk semiconductor layer is then thinned to the desired thickness. An amorphous doped semiconductor material is applied to the back surface of the thinned wafer and exposed to pulsed laser energy having a duration and intensity long enough to melt the amorphous material, but short enough to prevent thermal damage to the bondline. A back surface dielectric, backside contact mask and back surface reflector metal complete the cell.

Abstract: Disclosed is a method of welding a temperature-sensing thermocouple to a silicon wafer for sensing the temperature of the wafer during rapid thermal processing using TIG welding and/or electron-beam welding. In one embodiment, a ball of silicon is formed on the bead at one end of a thermocouple by placing the thermocouple on a silicon chip and then melting the silicon chip with a TIG welder. The ball and thermocouple are then placed on the surface of a silicon wafer and the ball and surface are then melted whereby the ball of silicon flows into the silicon wafer. In placing the thermocouple on an edge portion of a silicon wafer, the wafer is supported on a tantalum plate with the edge portion of the wafer extending beyond the plate. A molybdenum sheet is positioned on the top surface of the wafer with the edge portion of the wafer exposed. A TIG arc is established with the molybdenum layer and then the arc is moved to the edge portion of the wafer for melting the silicon.

Abstract: A method for converting solar energy to electricity is provided using solid-liquid interface photoelectrochemical cells wherein the liquid phase comprises a nonaqueous solvent, an electrolyte dissolved therein forming an ionically conductive solution and a redox couple suitable to accept and donate electrons from and to the electrodes. The redox couple is present in an amount sufficient to sustain a predetermined current and the concentrations of the electrolyte and redox couple in the solution are sufficient to provide no greater than a selected small voltage drop relative to the output voltage of the cell. The efficiency of conversion of light to electrical energy of such photoelectrochemical cells is 10% and greater.

Abstract: An interconnected array of solar cell or photodiode devices is formed by a method which includes the steps of forming on one major surface of a semiconductor wafer a plurality of said devices, forming grooves in said one major surface extending partway into said substrate between adjacent said devices, forming an oxide layer on selected portions of said one major surface and on the surfaces of said grooves, filling the grooves with an insulating material, forming metal interconnects between adjacent devices extending over said grooves and insulating material, attaching said one major surface to an insulating support, and severing through the wafer into the grooves from the other major surface to separate adjacent devices while leaving the metal interconnects.

Abstract: A process for controlled surface reactions in semiconductor material which includes rapidly heating the material to a high temperature, maintaining the temperature for a short time and cooling the material all while the surface is exposed to a substance which reacts at the surface.

Abstract: A solar cell including a pulse annealed layer of crystalline, amorphous or polycrystalline semiconductor material of one conductivity type and either a layer of opposite conductivity type or a liquid electrolyte forming a collector junction therewith. A method of improving the characteristics of a solar cell including at least one layer of crystalline, amorphous or polycrystalline semiconductor material which includes the step of pulse annealing said semiconductor material.

Abstract: A dynamic random access memory cell including a storage capacitor defined by an electrode and dielectric layers on both sides of said electrode and a transistor for controlling the charge on said storage capacitor.

Abstract: A solar cell comprising layers of n-type and p-type crystalline or substantially crystalline semiconductor material separated by a layer of amorphous semiconductor material having a larger coefficient of absorption than the outer p-type and n-type layers.

Abstract: Solid-liquid interface photoelectrochemical cells are provided wherein the liquid phase comprises a nonaqueous solvent, an electrolyte dissolved therein forming an ionically conductive solution and a redox couple suitable to accept and donate electrons from and to the electrodes. The redox couple is present in an amount sufficient to sustain a predetermined current and the concentrations of the electrolyte and redox couple in the solution are sufficient to provide no greater than a selected small voltage drop relative to the output voltage of the cell. The efficiency of conversion of light to electrical energy of such photoelectrochemical cells are 10% and greater.

Abstract: A solar cell having a solar absorbing layer of truly amorphous or microcrystalline semiconductor material or mixture thereof with means cooperating with said layer for collecting carriers generated by the solar energy. Said solar cell also including means for causing the solar energy to twice pass through the solar energy absorbing layer.

Abstract: A solar cell having single crystal or polycrystalline n-type and p-type layers separated by an amorphous layer.

Abstract: A semiconductor integrated circuit structure in which the inset regions are ion implanted and laser annealed to maintain substantially the dimensions of the implantation and the method of forming inset implanted regions having controlled dimensions.

Abstract: A programmable read only memory (PROM) includes a first plurality of conductive lines, a second plurality of conductive lines and polycrystalline silicon material therebetween. At the crossing points of the first and second plurality of lines doped regions are provided in the polycrystalline silicon in contact with a second line and which extend at least partially through the material. To provide a diode interconnect at any crossing point, the associated region is irradiated by a laser beam to either cause diffusion of dopant atoms to the underlaying conductive line or activate implanted ions, thereby electrically interconnecting the first and second lines through a diode. The PROM is readily fabricated as part of a monolithic integrated circuit or electrical array and can be programmed after completion of the fabrication process.

Abstract: A method of making a composite conductive structure is described. The structure includes an insulating substrate on which is provided a conductor of a refractory metal substantially nonreactive with silicon dioxide covered by a layer of a silicide of the refractory metal and a layer of silicon dioxide. The method includes depositing a layer of polycrystalline silicon over the conductor and the insulating substrate, reacting the layer of polycrystalline silicon with the conductor to form a refractory metal silicide, removing the unreacted portion of the layer of polycrystalline silicon, and then oxidizing the exposed surface of the refractory metal silicide into a layer of silicon dioxide.

Abstract: There is described a semiconductor solar cell of improved efficiency. The cell has a built-in electric field which extends from the surface of the cell to the interior to keep minority carriers away from the surface whereby recombination at the surface is reduced. Interior contacts are provided whereby current flow along the surface of the device to contacts is avoided to reduce surface resistance and recombination.

Abstract: Low resistance, doped polycrystalline semiconductor connection patterns are fabricated by scanning a doped polycrystalline layer with a laser beam thereby increasing the crystal grain size, reducing defects in the grains, increasing charge carrier mobility and as a result reducing material resistivity. Semiconductor devices having increased circuit density and speed are realized through use of laser annealed polycrystalline semiconductor resistors, contacts and interconnections.

Abstract: There is described efficient semiconductor p-n junction solar cells which can be made from defect-rich semiconductor material. The solar cells include an extended electric field surrounding the p-n junction for extracting the photo-generated carriers in the presence of defects which would otherwise reduce the efficiency of the cell. There is also described a method of fabricating efficient semiconductor p-n junction solar cells.