Abstract: A resonator comprises a quartz resonator element (11) sealed between a pair of flat quartz housing members (12, 13) the resonator comprises an active central region 110 defined by an annular recess 111 within which vibrational energy is trapped. The crystal orientation of the housing may be aligned with that of the resonator to minimise thermal effects.

Abstract: In a pulsed radio frequency plasma deposition process the pulse repetition frequency is matched to the gas exchange rate. This is achieved by using a pulse width of 50 to 500 microseconds and a pulse repetition rate corresponding to the time within which gas is exchanged in the reaction region.

Abstract: In a pulsed plasma process for surface treatment of a substrate the containing reactor vessel (11) has an inner cross-section conforming to the substrate geometry so as to confine the intense plasma region to the substrate surface (12). Preferably this region should be within 15 to 20 mm of the surface. Advantageously the inner surface is provided by a demountable insert (13).

Abstract: Discontinuities, e.g. scratches, in a plastics surface are removed by exposing the surface to a pulsed radio frequency plasma comprising a mixture of argon and hydrogen. After melting has been effected the surface is exposed to an argon plasma to effect cross-linking to form a smooth surface layer.

Abstract: An optical fibre is provided with a moisture barrier layer by exposing a plastics coating on the fibre to a pulsed plasma in order to modify the surface, for instance by implantation of silicon and/or by the deposition on the plastics layer an inorganic layer such as a non-stoichiometric composition of silicon and carbon or silicon and nitrogen.

Abstract: An apparatus for depositing metal or alloy films by a thermal decomposition process on a substrate includes a furnace having a number of selectively heated zones. The temperature of each zone is controllable so as to provide compensation for changes in the concentration of reactant materials in the different regions of the furnace. Means are provided for the safe handling of highly pyrophoric organometallic reactants. The apparatus may be used for the deposition of aluminium/silicon alloy films on semiconductor wafers in the manufacture of integrated circuits.

Abstract: Aluminum metallization layers on a semiconductor substrate are alloyed with a predetermined quantity of silicon by implanting silicon ions into the metallization layer. The layer is heated during subsequent processing to a temperature of 300.degree. to 500.degree. C. at which simultaneous annealing and diffusion take place to form the alloy.An apparatus for performing the process comprises a vacuum chamber wherein implantation is effected, an ion gun and means including a deflection magnet slit for selecting a single ionic species for implantation.

Abstract: Aluminum conductor tracks are formed e.g. on a semiconductor body by vapor depositing a layer of aluminum from tri-isobutyl aluminum and then selectively etching the routing. The surface of the semiconductor body is activated in a hydrogen discharge in the presence of a transport metal.

Abstract: A method for the deposition of aluminum on a solid body of pyrolysis of tri-isobutyl aluminum vapor diluted with an inert carrier gas.

Abstract: Silicon semiconductor devices, e.g. integrated circuits are metallized with a silicon/aluminum alloy by exposure to silane and an aluminum alkyl vapour at an elevated temperature and reduced pressure. The process eliminates the prior hydrogen plasma treatment and subsequent annealing of conventional vacuum deposition of aluminum and provides good step and crack coverage.

Abstract: A high power microscope is fitted with a gas jet arrangement for blowing a thin flexible mask into local contact with a semiconductor substrate so as to facilitate mask alignment.

Abstract: Aluminum films on a semiconductor surface are etched in a carbon tetrachloride glow discharge. Typical etch rates are 2000-3000 A/min. The addition of 15% ammonia to the plasma prevents HCl formation when the etched material is exposed to air.This process provides a more easily controlled process for the manufacture of high density integrated circuits.

Abstract: A conventional construction thyristor is modified to remove the short from the shorted emitter which is then led out to a separate pin for external connection. This enables the use of a simpler zero voltage switching control circuit.

Abstract: This relates to an optically isolated switching device made by coupling the output of a light emitting diode into a thyristor. Sensitivity is determined by optical flux density rather than total flux. Improved sensitivity is obtained with a mesa construction of a diode mounted on and bonded to a thyristor at a window in its cathode via a glass preform having a high refractive index.