Abstract: A Semiconductor device including, on at least one surface of a layer made of a crystalline semiconductor material of a certain type of conductivity, a layer made of an amorphous semiconductor material, doped with a type of conductivity opposite to the type of conductivity of the crystalline semiconductor material layer, characterized in that the concentration of the doping elements in the amorphous semiconductor layer varies gradually.

Abstract: A method for cleaning the surface of a silicon substrate, covered by a layer of silicon oxide includes: a) exposing the surface for 60 to 900 seconds to a radiofrequency plasma, generated from a fluorinated gas, to strip the silicon oxide layer and induce the adsorption of fluorinated elements on the substrate surface, the power density generated using the plasma being 10 mW/cm2 to 350 mW/cm2, the fluorinated gas pressure being 10 mTorrs to 200 mTorrs, and the substrate temperature being lower than or equal to 300° C.; and b) exposing the surface including the fluorinated elements for 5 to 120 seconds to a hydrogen radiofrequency plasma, to remove the fluorinated elements from the substrate surface, the power density generated using the plasma being 10 mW/cm2 to 350 mW/cm2, the hydrogen pressure being 10 mTorrs to 1 Torr, and the substrate temperature being lower than or equal to 300° C.

Abstract: A method is described of depositing film of an amorphous or microcrystalline material, for example silicon, from a plasma on to a substrate. Microwave energy is introduced into a chamber as a sequence of discrete microwave pulses, a film precursors gas is introduced into the chamber as a sequence of discrete gas pulses, and gas for generating atomic hydrogen is supplied to the chamber at least during each microwave pulse. Each microwave pulse is followed in non-overlapping fashion with a precursor gas pulse, and each precursor gas pulse is followed by a period during which there is neither a microwave pulse nor a precursor gas pulse.

Abstract: A method is described for forming a film of amorphous silicon (a-Si:H) on a substrate by deposition from a plasma. The substrate is placed in an enclosure, a film precursor gas is introduced into the enclosure, and unreacted and dissociated gas is extracted from the enclosure so as to provide a low pressure in the enclosure. Microwave energy is introduced into the gas within the enclosure to produce a plasma therein by distributed electron cyclotron resonance (DECR) and cause material to be deposited from the plasma on the substrate. The substrate is held during deposition at a temperature in the range 200-600° C., preferably 225-350° C. and a bias voltage is applied to the substrate at a level to give rise to a sheath potential in the range ?30 to ?105V, preferably using a source of RF power in the range of 50-250 mW/cm2 of the area of the substrate holder.

Abstract: The invention relates to a semiconductor device comprising: a crystalline semiconductor substrate (1) having a front face (1a) and a rear face (1b); a front passivation layer (3) placed on the front face (1a) of the substrate (1); a rear passivation layer (2) placed on the rear face (1b) of the substrate (1); a first metallization zone (10) placed on the rear passivation layer (2) and designed for collecting electrons; a second metallization zone designed for collecting holes, comprising: a surface portion (11) placed on the rear passivation layer (2); and an internal portion (12) passing through the rear passivation layer (2) and forming, in the substrate (1), a region in which the concentration of electron acceptors is greater than the rest of the substrate (1). The invention also relates to a module of photovoltaic cells using this device and to a process for manufacturing this device.

Abstract: Method of fabricating a multilayer film having at least one ultrathin layer of crystalline silicon, the film being fabricated from a substrate having a crystalline structure and including a previously-cleaned surface. The method includes the steps of: a) exposing the cleaned surface to a radiofrequency plasma generated in a gaseous mixture of SiF4, hydrogen, and argon, so as to form an ultrathin layer of crystalline silicon having an interface sublayer in contact with the substrate and containing microcavities; b) depositing at least one layer of material on the ultrathin layer of crystalline silicon so as form a multilayer film, the multilayer film including at least one mechanically strong layer; and c) annealing the substrate covered in the multilayer film at a temperature higher than 400° C., thereby enabling the multilayer film to be separated from the substrate.

Abstract: A method for cleaning the surface of a silicon substrate, covered by a layer of silicon oxide includes: a) exposing the surface for 60 to 900 seconds to a radiofrequency plasma, generated from a fluorinated gas, to strip the silicon oxide layer and induce the adsorption of fluorinated elements on the substrate surface, the power density generated using the plasma being 10 mW/cm2 to 350 mW/cm2, the fluorinated gas pressure being 10 mTorrs to 200 mTorrs, and the substrate temperature being lower than or equal to 300° C.; and b) exposing the surface including the fluorinated elements for 5 to 120 seconds to a hydrogen radiofrequency plasma, to remove the fluorinated elements from the substrate surface, the power density generated using the plasma being 10 mW/cm2 to 350 mW/cm2, the hydrogen pressure being 10 mTorrs to 1 Torr, and the substrate temperature being lower than or equal to 300° C.

Abstract: The invention relates to a method for texturing the surface of a gaseous phase silicon substrate, and to a textured silicon substrate for a solar cell. The method includes at least a step a) of exposing the surface to an SF6/O2 radiofrequency plasma for a duration of 2 to 30 minutes in order to produce a silicon substrate having a textured surface having pyramidal structures, the SF6/O2 ratio being 2 to 10. During step a) the power density generated using the radiofrequency plasma is greater than or equal to 2500 mW/cm2, and the SF6/O2 pressure in the reaction chamber is lower than or equal to 100 mTorrs, so as to produce a silicon substrate having a textured surface having inverted pyramidal structures.

Abstract: The subject of the invention is an anode material of the silicon-carbon composite type, for a lithium cell, having a high mass capacity and good cycling stability. This material is obtained by a preparation method comprising the steps consisting of: a) providing a silicon powder obtained by the plasma-enhanced chemical vapor deposition (PECVD) technique or by CO2 laser, the size of the silicon particles being less than 100 nm; b) mixing the silicon powder with a carbon-containing polymer, and c) carrying out the pyrolysis of the mixture. The invention also proposes a lithium cell containing at least one anode the material of which contains the nanocomposite material produced by this method.

Abstract: A photovoltaic module includes at least two photovoltaic cells in series, each rectangular cell including, respectively, a first rear thin film electrode, a photovoltaic stack having at least two active materials included between the rear electrode and a transparent conductive electrode made of a thin film, the electrode TC being capable of collecting and transmitting an electric current generated by the photovoltaic stack, the two photovoltaic cells being electrically connected in series by an electrical contact strip that is included between the electrode TC of the first cell and the rear electrode of the second cell. The local thickness of the electrode TC of the cell varies as a function of the distance to the electrical contact strip. Also described are methods for depositing and etching the transparent conductive film so as to simultaneously manufacture a plurality of cells for a single module.

Abstract: A method is described of forming a film of an amorphous material on a substrate (14) by deposition from a plasma. The substrate (14) is placed in an enclosure, a film precursor gas is introduced into the enclosure through pipes (20), and unreacted and dissociated gas is extracted from the enclosure through pipes (22) so as to provide a low pressure therein. Microwave energy—is introduced into the gas within the enclosure as a sequence of pulses at a given frequency and power level to produce a plasma therein by distributed electron cyclotron resonance (DECR) and cause material to be deposited from the plasma on the substrate. The frequency and/or power level of the pulses is altered during the course of deposition of material, so as to cause the bandgap to vary over the thickness of the deposited material.

Abstract: A method of fabricating semiconductor nanowires (5) on a substrate (1) having a metallic oxide layer (2), includes: a) exposing the metallic oxide layer to a hydrogen plasma (11) of power P for a duration t suitable for reducing the layer and for forming metallic nanodrops (3) of radius (Rm) on the surface of the metallic oxide layer; b) low temperature plasma-assisted deposition of a thin layer (4) of a semiconductor material on the metallic oxide layer including the metallic nanodrops, the thin layer having a thickness (Ha) suitable for covering the metallic nanodrops; and c) thermal annealing at a temperature T sufficient to activate lateral growth of nanowires by catalysis of the material deposited as a thin layer from the metallic nanodrops. Also described are nanowires obtained by this method and nanometric transistors including a semiconductor nanowire, for forming a semiconductive connection between a source (16), a drain (17), and a gate (18).

Abstract: A method is described of forming a film of an amorphous material on a substrate by deposition from a plasma. The substrate is placed in an enclosure, a film precursor gas is introduced into the enclosure, and unreacted and dissociated gas is extracted from the enclosure so as to provide a low pressure therein. Microwave energy is introduced into the gas within the enclosure to produce a plasma therein by distributed electron cyclotron resonance (DECR) and cause material to be deposited from the plasma on the substrate. The said flow rate of the film precursor gas is altered during the course of deposition of material, so as to cause the bandgap to vary over the thickness of the deposited material.

Abstract: A Semiconductor device including, on at least one surface of a layer made of a crystalline semiconductor material of a certain type of conductivity, a layer made of an amorphous semiconductor material, doped with a type of conductivity opposite to the type of conductivity of the crystalline semiconductor material layer, characterized in that the concentration of the doping elements in the amorphous semiconductor layer varies gradually.

Abstract: A semiconductor device including, on at least one surface of a crystalline semiconductor substrate, at least one first amorphous semiconductor region doped with a first type of conductivity. The semiconductor substrate includes, on the same at least one surface, at least one second amorphous semiconductor region doped with a second type of conductivity, opposite the first type of conductivity. The first amorphous semiconductor region, insulated for the second amorphous semiconductor region by at least ore dielectric region in the contact with the semiconductor substrate, and the second amorphous semiconductor region form an interdigitated structure.

Abstract: A transistor for active matrix display and a method for producing the transistor (1). The transistor (1) includes a microcrystalline silicon film (5) and an insulator (3). The crystalline fraction of the microcrystalline silicon film (5) is above 80%. According to the invention, the transistor (1) includes a plasma treated interface (4) located between the insulator (3) and the microcrystalline silicon film (5) so that the transistor (1) has a linear mobility equal or superior to 1.5 cm2V?1s?1, shows threshold voltage stability and wherein the microcrystalline silicon film (5) includes grains (6) whose size ranges between 10 nm and 400 nm. The invention concerns as well a display unit having a line-column matrix of pixels that are actively addressed, each pixel comprising at least a transistor as described above.

Abstract: A crystallographically textured metallic substrate includes surfaces for connection and for receiving a thin layer deposit, and is made up of an alloy presenting a cubic crystalline system with centered faces and a predominantly cubic crystallographic texture {100}<001>, the receiving surface including grains mainly presenting crystallographic planes {100} parallel to the receiving surface. The alloy is iron-nickel with weight % relative to total weight: Ni?30%, Cu?15%, Cr?15%, Co?12%, Mn?5%, S<0.0007%, P<0.003%, B<0.0005%, Pb<0.0001%, and in the alloy: 34%?(Ni+Cr+Cu/2+Co/2+Mn). The alloy includes up to 1% in weight of one or several deoxidizing elements chosen among silicon, magnesium, aluminium and calcium, the rest of the elements in the alloy being iron and impurities.

Abstract: The invention concerns a photoactive nanocomposite (3) comprising at least one donor-acceptor couple of semiconductor elements. One of the elements is made of doped nanowires (7) with sp3 structure, and the other of the elements is an organic compound (8). The elements are supported by a device substrate (1). The invention also concerns a production method. According to a first embodiment, after their growth, the nanowires (7) are retrieved, functionalised and solubilised in the organic component (8). The mixture is deposited by coating on a device substrate. According to a second embodiment, the nanowires (7) are formed on a growth substrate (5) which is also the device substrate. The organic component (8) is combined with the nanowires (7) so as to form an active layer (3). Such a photoactive nanocomposite (3) allows production of a photovoltaic cell.

Abstract: An apparatus is described for depositing a film on a substrate from a plasma. The apparatus comprises an enclosure, a plurality of plasma generator elements disposed within the enclosure, and means, also within the enclosure, for supporting the substrate. Each plasma generator element comprises a microwave antenna having an end from which microwaves are emitted, a magnet disposed in the region of the said antenna end and defining therewith an electron cyclotron resonance region in which a plasma can be generated, and a gas entry element having an outlet for a film precursor gas or a plasma gas. The outlet is arranged to direct gas towards a film deposition area situated beyond the magnet, as considered from the microwave antenna, the outlet being located in, or above, the hot electron confinement envelope.

Abstract: A method is described of forming a film of an amorphous material on a substrate (14) by deposition from a plasma. The substrate (14) is placed in an enclosure, a film precursor gas is introduced into the enclosure through pipes (20), and unreacted and dissociated gas is extracted from the enclosure through pipes (22) so as to provide a low pressure therein. Microwave energy—is introduced into the gas within the enclosure as a sequence of pulses at a given frequency and power level to produce a plasma therein by distributed electron cyclotron resonance (DECR) and cause material to be deposited from the plasma on the substrate. The frequency and/or power level of the pulses is altered during the course of deposition of material, so as to cause the bandgap to vary over the thickness of the deposited material.