Abstract: A support for a sheet of glass is disclosed. The support comprises first and second support assemblies each comprising a respective base and arm assembly. Each arm assembly comprises a respective first arm having first and second ends and a first contact surface at each end thereof for contacting a first major surface of the sheet of glass when the sheet of glass is supported on the support. Each arm assembly is coupled to the respective base by a respective coupling for rotation about a pivot axis. Any of the first contact surfaces may be provided by a ball castor or wheel. The support is useful when supporting the glass sheet wherein a measurement of the shape thereof is required because the support is able to quickly reach an equilibrium configuration. A method of supporting a glass sheet using the support is also disclosed.

Abstract: A method for determining the thickness of a film on a substrate is described. The substrate has a first major surface opposite a second major surface, and the film covers a portion of the first major surface. During a first measurement step, a first measuring beam is used to determine the distance from a first reference point to a portion of the first major surface of the substrate that is not covered with the film, and a second measuring beam is used to determine the distance from a second reference point to a portion of the second major surface of the substrate that is not covered with film. During a second measurement step the first measuring beam is used to determine the distance from the first reference point to the film, and the second measuring beam is used to determine the distance from the second reference point to a portion of the second major surface of the substrate that is not covered with film.

Abstract: A semiconductor device is disclosed in which a barrier layer is deposited on the sides of the mesa. The barrier layer may comprise a semiconductor material. The barrier layer reduces diffusion of dopants into the active region of the device.

Abstract: An oxide layer on an indium phosphide semiconductor substrate is doped with silicon. This enables epitaxial layers to be deposited upon the substrate in a conventional manner, including mesa etching and overgrowth, to form a semiconductor structure. The doped oxide layer is thought to reduce diffusion of phosphorus out of the substrate and thus to reduce the zinc levels in the active region of the structure. Additionally, or as an alternative, after mesa etching oxide can be formed on the mesa sides and then doped with silicon. Conventional blocking layers can then be formed over the doped oxide, reducing the diffusion of zinc from the blocking layers into the rest of the structure.

Abstract: An oxide layer on an indium phosphide semiconductor substrate is doped with silicon. This enables epitaxial layers to be deposited upon the substrate in a conventional manner, including mesa etching and overgrowth, to form a semiconductor structure. The doped oxide layer is thought to reduce diffusion of phosphorus out of the substrate and thus to reduce the zinc levels in the active region of the structure. Additionally, or as an alternative, after mesa etching oxide can be formed on the mesa sides and then doped with silicon. Conventional blocking layers can then be formed over the doped oxide, reducing the diffusion of zinc from the blocking layers into the rest of the structure.

Abstract: The present invention relates to a semiconductor device (1) with one or more current confinement regions (20) and to a method of manufacturing such a device, particularly buried heterostructure light emitting devices such as semiconductor lasers and light emitting diodes. The device comprising a doped semiconductor substrate (2) of a first conduction type, a buried heterojunction active layer (10) above the substrate (2), a current conduction region (4) above the active layer (10), one or more current confinement regions (20) formed over the substrate (2) adjacent the active layer (10), the current conduction region (4) and current confinement region (20) being arranged in use to channel electric current to the active layer (10).