Mitsubishi Denki Kabushiki Kaisha

Mikio Deguchi

Hiroaki Morikawa

Satoshi Arimoto

Hajime Sasaki

Satoshi Hamamoto

Kazuhiko Satoh

Takushi Itagaki

Hideo Naomoto

Masaaki Usui

Kazuyasu Fujishima

Yasushi Terada

Norio Hayafuji

Hisao Kumabe

Yoshitatsu Kawama

Shigeru Mitsui

In a method for fabricating a thin film solar cell, a thin semiconductor film serving as a power generating layer is formed on a substrate via an intermediate layer, a plurality of holes are formed penetrating through the thin semiconductor film and reaching the intermediate layer, and the intermediate layer is etched away through the through-holes, separating the thin semiconductor film from the substrate with high-efficiency. Since stress is hardly applied to the thin semiconductor film during the separation process, cracking and breaking of the semiconductor film is avoided. Further, since the surface of the substrate is maintained in good condition, the substrate can be reused, resulting in a reduction in the production cost.

Method for producing thin film solar cell

An apparatus for zone-melting recrystallization of semiconductor films on semiconductor substrates includes a heater disposed opposite the front surface of a semiconductor substrate and moving across the semiconductor substrate at a uniform rate. The heater may be a strip heating element covered with an insulating and refractory material radiating less heat than the strip heating element. Since heat emitted from surfaces of the heating element except the surface opposite the substrate is intercepted by the insulating and refractory film, the width of the molten zone produced in the semiconductor film is reduced.

Zone-melting recrystallization of semiconductor materials

A method for producing a semiconductor structure including a semiconductor film formed on a semiconductor substrate body via an insulating film includes: laminating a first insulating film, a first semiconductor film, and a second insulating film on the semiconductor substrate successively; forming stripe-shaped second semiconductor films of predetermined width on the second insulating film arranged periodically at a predetermined interval and covering these second semiconductor films with a third insulating film; performing zone melting recrystallization of the first semiconductor film from one end of the substrate to the opposite end along the stripe direction of the stripe-shaped second semiconductor film; etching the third insulating film and portions of the second insulating film not sandwiched by the first and second semiconductor films; oxidizing portions of the second semiconductor film and the first semiconductor film exposed in the etching step and etching and removing the second insulating film remaining after the previous etching. Thus, a semiconductor substrate including a recrystallized semiconductor film having removed sub-grain-boundaries generated during the zone melting recrystallization, is obtained by fewer process steps than in the prior art.

Method of producing a semiconductor structure including a recrystallized

A method for producing a thin-film solar cell having a thin-film active layer on a graphite sheet substrate includes the steps of adhering two sheets of graphite together, forming semiconductor thin films serving as active layers on second main surfaces of the two sheets of graphite, and separating the two sheets of graphite from each other. In this structure, stress caused by a difference in expansion coefficients between the upper sheet and the semiconductor thin film is cancelled by stress caused by a difference in expansion coefficients between the lower sheet and the semiconductor thin film. Therefore, curvature of the substrates is prevented whereby subsequent process steps are easily carried out. In addition, the number of products per unit time is doubled, thereby increasing productivity.

Thin film solar cell and production method therefor

In a method of producing a thin-film solar cell, a graphite sheet in which the breaking stress in a thickness direction is smaller than the breaking stress in a direction perpendicular to the thickness direction is adhered to a heat resistant substrate, a semiconductor thin film is formed on the graphite sheet in a high temperature process, a second substrate for supporting the semiconductor thin film is adhered to the semiconductor thin film, and the graphite sheet is broken by applying a mechanical stress to the heat resistant substrate and the second substrate. The semiconductor thin film is reliably supported by the heat resistant substrate during high temperature processing and easily removed from the heat resistant substrate by breaking the graphite sheet. In addition, since the graphite sheet has an anisotropic breaking stress, fragments of the graphite sheet remaining on the surface of the semiconductor thin film are easily removed. As a result, a high quality thin film solar cell is produced reliably at low cost.

Method of producing thin-film solar cell

Thin-film solar cell

A method for producing a thin-film solar cell having a thin-film active layer on a graphite sheet substrate includes the steps of adhering two sheets of graphite together, forming semi-conductor thin films serving as active layers on second main surfaces of the two sheets of graphite, and separating the two sheets of graphite from each other. In this structure, stress caused by a difference in expansion coefficients between the upper sheet and the semiconductor thin film is cancelled by stress caused by a difference in expansion coefficients between the lower sheet and the semiconductor thin film. Therefore, curvature of the substrates is prevented whereby subsequent process steps are easily carried out. In addition, the number of products per unit time is doubled, thereby increasing productivity.

Method of producing a thin-film solar cell

A semiconductor device includes a porous, electrically insulating substrate, a semiconductor film disposed on the substrate, and a metal filling the pores of the substrate, the metal contacting the semiconductor film at the interface of the substrate and the semiconductor film.

Semiconductor device and method for manufacturing the same

A method for fabricating a recrystallized semiconductor film includes forming a polycrystalline or amorphous semiconductor film on a base having a melting point or softening temperature lower than the melting point of the semiconductor film, heating the base to melt it with a first heater, and melting the semiconductor film with a second heater and recrystallizing the semiconductor film while the base is molten. Thereby, generation of stress in the semiconductor film is prevented or reduced and the planarity of the semiconductor film is not damaged by distortion of the substrate and the temperature in the semiconductor film is uniform at the time of recrystallization. As a result, a recrystallized film with good crystallinity is obtained.

Method for fabricating recrystallized semiconductor film

An electrode structure of a solar cell includes a metal wire fixed to the light incident surface of the solar cell with an electrically conductive adhesive. An electrode production method of a solar cell includes applying an electrically conductive adhesive to at least one of a portion of a metal wire and a portion of the light incident surface of the solar cell, pressing the metal wire into a predetermined position of the light incident surface of the solar cell, and solidifying the conductive adhesive to fix the metal wire.

Method of making a solar cell electrode

A semiconductor device has a plurality of unit photovoltaic elements arranged on a substrate and connected to each other in series. The photovoltaic device includes first semiconductor layers with low resistivity formed on a high-temperature-resistant insulating substrate and spaced apart at a predetermined interval and second semiconductor layers selectively formed on corresponding first semiconductor layers so that a part of the respective first semiconductor layer is exposed. The second semiconductor layer is not in contact with the first semiconductor layer of an adjacent unit photovoltaic element. An electrode formed on the second semiconductor layer is in contact with the first semiconductor layer of the adjacent unit photovoltaic element. As a result, there is provided a photovoltaic semiconductor device comprising a plurality of unit photovoltaic elements connected to each other in series with high conversion efficiency and which is not easily degraded by light irradiation.

Photovoltaic semiconductor device and method for manufacturing the same

Solar cell and solar cell array with adhered electrode

An apparatus for treating wafers utilizing the plasma produced by a gas discharge and a method of cleaning such apparatus are disclosed. The apparatus is equipped with a device for forming a high voltage electric field in a space outside of the discharge space in which the wafer treating plasma is generated. The cleaning of the inner surfaces of the vacuum vessel of the apparatus is effected during the periods between the treatments by means of the plasma generated by the gas discharge started and sustained by the electric field device as well as by a main electrode for maintaining the treating discharge. The device for forming a high voltage electric field as mentioned above may comprise a limiter electrode surrounding the treating discharge space; alternatively, it may comprise an auxiliary electrode disposed in the space outside the treating discharge space. First, an etching gas capable of etching the films deposited on the inner surfaces of the vessel of the apparatus is introduced into the vessel as the discharge gas in the cleaning process; next, hydrogen is introduced into the vessel to remove the impurities adsorbed on the surfaces of the vessel. The etching gas may comprise hydrogen or argon.

Apparatus for producing semiconductor devices

Each of the memory cells forming a nonvolatile RAM comprises one floating-gate transistor and one capacitor. When the power source is turned on, storage of information is performed according to the amount of electric charge stored in each capacitor. When the power source is turned off, nonvolatile storage of information is performed according to the level of the threshold voltage of each floating-gate transistor.

Growing community of inventors

Itami, Japan

Mikio Deguchi