Abstract:
A structure for doping of III-V compounds is provided. The structure is a multi-layered structure in which layers of dopant are alternated with layers of initially undoped III-V compound. Dopant diffuses from the layers of dopant into the layers of III-V compound. The structure does not facilitate the introduction of impurities into the III-V compound during the diffusion of the dopant.
Abstract:
To secure accurate control over rapid diffusion such as the diffusion of zinc into gallium arsenide, the source and slices to be processed are isolated from one another during an initial warm-up period. This is done using one vessel for the crystal slice and a second vessel for the source. The source vessel initially blocks an opening in the slice vessel while the source and slice are brought to the desired diffusion temperature. The source vessel is then slid through the opening to a diffusing position in which a trailing part of the source vessel again plugs the opening in the slice vessel and in which an open part of the source vessel is now in the interior of the slice vessel. Use of this arrangement avoids the uncontrolled diffusion which occurs in current diffusion capsules during initial heating of the capsule.
Abstract:
In the manufacture of double heterostructure laser diodes using liquid phase epitaxy a source crystal precedes the laser substrate crystal through the process to ensure saturation of the various melts from which epitaxial growth is obtained. The source crystal has hitherto been discarded. The source crystal, since it immediately precedes the substrate crystal, also experiences epitaxial growth of a heterostructure but with heterostructure layer thicknesses unsuited for laser diode fabrication. By suitable processing of the source crystal after it is formed with a heterostructure, light emitting diodes can be produced so contributing to a 50% reduction in materials cost.
Abstract:
An electro-optic device for stabilizing the output level of a Burrus-type light emitting diode (LED) utilizes a photodiode to monitor side emission from an active region of the LED. Side emission closely tracks top emission, which is launched into an output fiber. An electrical analog is derived from the monitored side emission and is applied in a feedback loop to control modulation level or bias current to the LED. In this way, peak optical output (for digital systems) or r.m.s. output and linearity (for analog systems) is stabilized. The monitoring photodiode and the LED may be spatially separate or may form a unitary structure.
Abstract:
A double heterostructure laser has a first confining layer on the substrate, an active layer on the first confining layer and a second confining layer on the active layer. A groove is etched through the second confining layer and active layer to form a reflecting surface at approximately 45.degree. to the plane of the active layer. The resonant cavity is formed between a cleaned end surface and a surface at the substrate. A hole through the substrate to the first confining layer is aligned with the reflecting surface for emission therethrough.
Abstract:
In a fabricating a III-V compound, for example, GaAs, having a layered structure a first layer is grown on a planar substrate by a vapor deposition process adapted to produce differential growth while a subsequent layer is grown by a deposition process which restores planarity. In this way a uniformly thick combination layer is produced with a non-planar junction between its composite layers. Particularly in the fabrication of channelled substrate double heterostructure lasers, a channelled blocking layer is grown by organo-metallic pyrolysis (OMP) and a subsequent confining layer is grown using liquid phase epitaxy (LPE). The OMP process produces a channel with flanking shoulder portions which permit LPE growth of a very thin confining layer immediately above the shoulder portions thereby improving linearity of the device.
Abstract:
In fabricating a III-V compound, for example, GaAs, having a layered structure a first layer is grown on a planar substrate by a vapor deposition process adapted to produce differential growth while a subsequent layer is grown by a deposition process which restores planarity. In this way, a uniformly thick combination layer is produced with a non-planar junction between its composite layers. Particularly in the fabrication of channelled substrate double heterostructure lasers, a channelled blocking layer is grown by organo-metallic pyrolysis (OMP) and a subsequent confining layer is grown using liquid phase epitaxy (LPE). The OMP process produces a channel with flanking shoulder portions which permit LPE growth of a very thin confining layer immediately above the shoulder portions thereby improving linearity of the device.
Abstract:
A surface emitting light emitting diode (LED) has a reflecting element to redirect light emitted away from the light emitting region towards an exit window. The LED bottom contact is formed over the reflecting element and a current confining path is set up within the LED to funnel current between the top and bottom contacts around the reflecting element and through the light emitting region.