Dow Corning Corporation

Ecole Polytechnique

Dow Corning S.a.

Dow Corning Europe Sa

Pierre Descamps

Patrick Leempoel

Pere Roca I Cabarrocas

Pavel Bulkin

Dmitri Daineka

Thibault Kervyn De Meerendre

Andreas Thomas Wolf

Martin Harvey

Thien Hai Dao

Thibault Kervyn De Meerendré

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.

Method and apparatus for forming a film by deposition from a plasma

A plasma excitation device is described for use in depositing a film on a substrate from a plasma formed by distributed electron cyclotron resonance. The device 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.

Device for forming a film by deposition from a plasma

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.

Method of forming a film by deposition from a plasma

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&#xb0; C., preferably 225-350&#xb0; C. and a bias voltage is applied to the substrate at a level to give rise to a sheath potential in the range &#x2212;30 to &#x2212;105V, preferably using a source of RF power in the range of 50-250 mW/cm2 of the area of the substrate holder.

Deposition of amorphous silicon films by electron cyclotron resonance

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 through pipes (), and unreacted and dissociated gas is extracted from the enclosure through pipes () so as to provide a low pressure therein. Microwave energy&#x2014;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.

Film deposition of amorphous films with a graded bandgap by electron cyclotron resonance

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.

Method for forming a film with a graded bandgap by deposition of an amorphous material from a plasma

An apparatus is provided for producing a plasma for a work surface, for example to deposit material thereon. The apparatus comprises an enclosure which contains an ionizable gas, a plurality of plasma excitation devices each of which is arranged to enable microwaves to travel from a first end thereof to a second end and radiate therefrom into the gas, and means for generating a magnetic field in the gas. A source of microwaves feeds microwaves to the first ends of the excitation devices. In use, regions exist within the said gas where the direction of the electric vector of the microwaves is non-parallel to the lines of the magnetic field, and the magnetic field has value B, and the microwaves have a frequency f such as to substantially satisfy the relationship: B=&#x3c0;mf D e where m and e are the mass and charge respectively of an electron.

Method and apparatus for creating a plasma

An improved method of making glass building elements filled with cured polydiorganosiloxane compositions. The method comprises first coating the interior surfaces of a hollow glass block with a first curable polydiorganosiloxane composition. This first composition is then cured. Next, the block is charged with a quantity of a second curable polydiorganosiloxane composition. This second composition is then cured to form the building element. The resultant element has improved aesthetics because of the decreased quantity of entrapped bubbles.

Method of making a building element

A method and apparatus for determining surface characteristics of a layer (e.g. anodised aluminum) by measuring electrical impedance thereof and solving specified equations.

Electrical testing process

The specification describes and claims a method of bonding a sealant to an anodised aluminium surface the method comprising the steps of (1) measuring the electrical impedance of anodised aluminium substrates, (2) selecting at least one substrate having an electrical phase shift of from 0.4 to 0.5, (3) cleaning the anodised surface of the substrate, (4) applying to the anodised surface a curable silicone sealant composition and (5) bringing about curing of the sealant composition to form a bond between the anodised surface and the sealant.

Method of sealing

A foamable silicone composition comprises a polysiloxane having silicon-bonded hydrogen atoms, a polysiloxane having siloxane units including unsaturated groups, a polysiloxane having silicon-bonded hydroxyl groups, a noble metal catalyst and from 3 to 40 parts by weight per 100 parts by weight of the composition of entities of borosilicate or silicate glass or mixtures thereof. The composition comprises first and second Parts A and B having viscosities which are sufficiently similar to each other to permit facile machine mixing of the Parts; the first Part comprises the noble metal catalyst and a portion of the entities and the second Part comprises the polysiloxane having silicon-bonded hydrogen atoms and a portion of the entities pretreated with a compatible silane or a polysiloxane having silicon-bonded hydrogen atoms. Preferred entities comprise hollow spherical particles or hollow entities which have an irregular configuration. Preferably the entities of the first Part of the composition have been treated with a compatible silane. Preferred compatible silanes are vinyl silanes. The compositions are suitable for producing rigid fire resistant foamed articles resistant to compression and deflection and may be used in the production of building elements.

Silicone foams

The specification describes and claims a method of making silicone foam compositions comprising the steps of introducing into a moulding cavity a quantity of foamable silicone compositions which is curable at room, or slightly elevated, temperature and bring about curing in the cavity to produce a cured silicone foam. The moulding cavity is closed prior to foaming thereby restricting expansion of the foam. The volume of the closed moulding cavity is a minimum 10% less than that which would be occupied by the composition if it foamed and cured at room temperature without restriction. Lower density foams formed by the above procedure may be converted into rigid elastomeric low density materials by a heat or microwave post cure. For a given composition and foam density the fire resistance of a foam produced by a method according to the invention is greater than a foam which is allowed to foam freely.

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Rixensart, Belgium

Pierre Descamps