Chevron Research Company

Daidosanso K. K.

Lewis M Fraas

Paul Stephen McLeod

John A Cape

Larry D Partain

Robert E Weiss

Paul M McLeod

A thermal cracking apparatus for cracking organic or inorganic gases is described. More particularly, the thermal cracker cracks inorganic gases such as arsine and phosphine for use in the growth of III-V compound semiconductor layers. The design of the apparatus minimizes the uptake of contaminants into the cracked gas stream.

Gaseous organic/inorganic thermal cracker for vacuum chemical epitaxy

A vacuum chemical epitaxy apparatus comprising a first mixing chamber having an inlet for introducing a metal-organic gaseous materials and n-type and p-type dopants, and a plurality of outlets for directing the flow of said metal-organic gases and n-type and p-type dopants toward a substrate; a second mixing chamber disposed below said first chamber having an inlet for introducing a metal-organic gaseous material and n-type and p-type dopants, and a plurality of passages through said first chamber and an outlet for each passage, wherein the passage outlets are in substantially the same plane with the outlets of the first chamber; and means for exhausting the metal-organic gaseous materials and n-type and p-type dopants from the second chamber.

Apparatus and process for vacuum chemical epitaxy

An injection block having a plurality of geometrically arranged injection sources for gaseous Group III metal organic compounds is oriented substantially perpendicular to the placement of at least one semiconductor wafer substrate within a vacuum reaction chamber. The injector sources are sized to provide disbursing flow of the compounds capable of depositing a layer of about 5% uniform thickness or less over substantially the entire semiconductor wafer. An injection source of Group V compounds is located centrally within the geometrically arranged injection sources for the Group III compounds. The Group V injection source is sized to supply an excess of the Group V compounds required to react with the Group III compounds in order to form Group III-V semiconductor layers on the substrate and partition the Group III sources into groups having substantially equal numbers of injection sources. An excess of Group V comounds is injected. The vacuum within the reaction chamber is adjusted at predetermined flow rates of the Group III compounds such that a mean-free path of the Group III compounds is greater than the distance from the injection source of the Group III compounds to the substrate. The substrate is heated to a temperature to which a reaction proceeds. The unreacted Group III compounds are exhausted from the vacuum chamber adjacent the edges of a substrate holder facing the top of the chamber opposite to the injection sources. In this manner, the disbursing flow of Group III compounds from the geometric arrangement of sources uniformly overlaps substantially the entire substrate and the algebraic sum of the fluxes from the Group III compound sources remains constant across the area of the substrate upon which the layer is to be deposited.

Process for vacuum chemical epitaxy

The present invention is an apparatus of mechanically stacked photovoltaic cells having two cells. The bottom cell has a layer of GaSb having regions of different conductivity forming a homojunction therein. The GaSb layer is sandwiched between a conductive substrate and a bottom passivating layer. In the bottom cell is a means for forming electrical contacts to the substrate and the incident surface of the bottom passivating layer. The top cell has a layer of GaAs having regions of different conductivity forming a homojunction therein, a top passivating layer contacting the surface of the layer of GaAs which is incident to solar radiation, and a means for forming electrical contacts to the layer of GaAs opposed to solar radiation and the incident surface of the passivating layer.

GaAs on GaSb mechanically stacked photovoltaic cells, package assembly,

A heater apparatus particularly suitable for use in a vacuum deposition apparatus is disclosed. The heater apparatus contains an open structure surrounding the heating element to permit quick evacuation of the apparatus and avoid memory problems attendant with sealed heater tubes used in a high vacuum environment which is repeatedly cycled from vacuum to ambient pressure.

Vacuum chamber heater apparatus

The present invention is an apparatus of mechanically stacked photovoltaic cells having a bottom heat spreader and a top heat spreader, a bottom photovoltaic cell and a top photovoltaic cell, and means for forming the necessary electrical contacts. The heat spreaders are electrically insulated from each other but are thermally connected to each other. The bottom photovoltaic cell has an anode and a cathode and is thermally bonded to the bottom heat spreader and is thermally connected to the top heat spreader. The top photovoltaic cell has an anode and a cathode, is electrically insulated from the bottom photovoltaic cell, and is thermally bonded to the top heat spreader and is thermally connected to the bottom heat spreader. The means for forming the necessary electrical contacts includes a means for electrically contacting the anode of the bottom photovoltaic cell, a means for electrically contacting the cathode of the bottom photovoltaic cell, a means for electrically contacting the anode of the top photovoltaic cell, and a means for electrically contacting the cathode of the top photovoltaic cell.

Mechanically stacked photovoltaic cells, package assembly, and modules

A photovolatic device is disclosed comprising a p-type conductive substrate, a sandwich of p-type Al.sub.y Ga.sub.(1-y) As bottom layer/p-type GaAs base layer/p-type Al.sub.y Ga.sub.(1-y) As top layer (wherein the surface area of the p-type Al.sub.y Ga.sub.(1-y) As top layer is less than the surface area of the p-type GaAs base layer, a layer of n.sup.+ -type GaAs emitter contacting the surface of the p-type GaAs base layer (wherein the surface area of the layer of n.sup.+ -type GaAs emitter is less than one-tenth the surface area of the p-type GaAs base layer), an insulating layer contacting the surface of the p-type Al.sub.y Ga.sub.(1-y) As top layer, and means for forming electrical contacts to the substrate and the incident surface of the n.sup.+ -type GaAsemitter layer.

Process for the fabrication of a gallium arsenide grating solar cell

A mechanically stacked module package is described. The package permits the effective mechanical stacking of two solar cells in a compact arrangement. The design also permits the easy wiring of the package into a voltage matching configuration for module wiring thus eliminating the problems of current matching the top and bottom cells. The package design can be used with any mechanically stacked cells although the design is most suitable for concentrator solar cell configurations where the removal of heat to avoid degradation and shortening of lifetime is a major concern.

Photovoltaic cell package assembly for mechanically stacked photovoltaic

Two- and three-terminal ternary III-V two-color and three-color solar cells which incorporate GaAs.sub.1-x-y P.sub.x Sb.sub.y transparent window layers are described. The window layers lower the surface recombination of the incident homojunction layer.

Ternary III-V multicolor solar cells containing a quaternary window

Three-terminal ternary III-V two-color solar cells incorporating layers of GaAs.sub.1-x-y P.sub.x Sb.sub.y. The three-terminal structure enables the current to be withdrawn from both cells without the necessity of current matching between the two color stacked photovoltaic device. In addition, the three-terminal configuration permits the independent determination of the individual properties of each cell. The stacked two-color cells can be connected in series through the three-terminal arrangement to overcome the problems of independent load matching between the cells encountered with the conventional two-terminal configuration. Finally, the three-terminal two colored solar cells does not require a shorting junction between the homojunction layers of the cells but only a simple transition layer. This speeds the processing of the device.

Three-terminal ternary III-V multicolor solar cells and process of

Ternary III-V multicolor solar cells incorporating layers of GaAs.sub.1-x-y P.sub.x Sb.sub.y and an improved process of fabricating multicolor photovoltaic III-V compound photovoltaic devices.

Ternary III-V multicolor solar cells and process of fabrication

A new high efficiency, multijunction photovoltaic solar cell for use with a concentrating lens. This cell comprises an elemental single crystal substrate without an internal light sensitive junction, upon which are two or more successive homogenous layers of semiconductor material, each layer containing within it a light sensitive p/n junction of a similar polarity, each layer having essentially the same lattice constant as the single crystal substrate, each layer having a shorting junction contact with the layer immediately above and below it, each successive layer adsorbing light energy at a shorter wavelength, and each layer being of sufficient thickness and appropriate composition to develop essentially the same current as the other layers. The outer surfaces of the top layer and the substrate are provided with electrical contacts for distribution of the electric current. The top contact comprises a layer of a transparent conductive material with electrical connections and the whole structure is completed with an antireflection coating over the top.

Multilayer photovoltaic cell

A new high efficiency, multijunction photovoltaic solar cell for use with a concentration lens. This cell comprises an elemental single crystal substrate without an internal light sensitive junction, upon which are two or more successive homogenous layers of semiconductor materials, each layer containing within it a light sensitive p/n junction of a similar polarity, each layer having essentially the same lattice constant as the single crystal substrate, each layer having a shorting junction contact with the layer immediately above and below it, each successive layer adsorbing light energy at a shorter wavelength, and each layer being of sufficient thickness and appropriate composition to develop essentially the same current as the other layers. At the junction, between the successive layers of the multilayer cell, a thin pseudo transparent low bandgap semiconductor layer is provided at the shorting junction interface. The outer surfaces of the top layer and the substrate are provided with electrical contacts for distribution of the electric current. The top contact comprises a layer of a transparent conductive material with electrical connections and the whole structure is completed with an antireflection coating over the top.

Growing community of inventors

El Sobrante, CA, United States of America

Lewis M Fraas