Abstract: In a semiconductor buried heterostructure laser having a mesa (2, 3, 4) and confinement layers (5, 6, 7) on a substrate (12), at least the lowermost of the confinement layers (5, 6, 7) is substantially planar up to the mesa. This is achieved by MOVPE growth of InP against lateral surfaces of the mesa (2, 3, 4) which are defined by distinct crystallographic planes of the material of the mesa. In particular (111) B InP planes are used. The laser is particularly for use in the field of optical communications.

Abstract: A semiconductor structure and methods for making it, for use in opto-electronic devices, employs only MOVPE growth steps. The structure is based on a mesa having substantially non-reentrant sides. To make it, an initial semiconductor structure is produced which comprises a substrate with a mesa thereon, the mesa having a self-aligned, central stripe of metal organic vapour phase growth suppressing material on its uppermost surface. Burying layers are then grown by MOVPE at either side of the mesa, the stripe removed, and covering layers grown over the mesa and adjoining regions of the burying layers. To make an opto-electronic device, a silica window can be formed on the uppermost surface of the covering layers and contacts provided through the window and to the remote face of the substrate. Two methods of making the initial semiconductor structure are described. Devices such as optical detectors and waveguides can be made using methods according to the invention.

Abstract: A semiconductor structure and methods for making it, for use in opto-electronic devices, employs only MOVPE growth steps. The structure is based on a mesa having substantially non-reentrant sides. An initial semiconductor structure is produced which includes a substrate with a mesa having a self-aligned, central stripe of metal organic vapor phase growth suppressing material on its uppermost surface. Burying layers are then grown by MOVPE at either side of the mesa, the stripe removed, and covering layers grown over the mesa and adjoining regions of the burying layers. To make an opto-electronic device, a silica window can be formed on the uppermost surface of the covering layers and contacts provided through the window and to the remote face of the substrate. Two methods of making the initial semiconductor structure are described. Devices such as optical detectors and waveguides can be made using methods according to the invention.

Abstract: A semiconductor device is disclosed that comprises a base semiconductor portion and, thereon, first and second elevated semiconductor portions separated by a channel. The uppermost surface of the first elevated semiconductor portion carries a metal electrical contact layer and the uppermost of the second a dielectric layer. The surfaces defining the channel are substantially free of metal and dielectric. The structure can be used in a ridge waveguide laser, the first elevated semiconductor portion constituting the ridge. Distributed feedback corrugations may be incorporated in such devices or in other ridge waveguide structures.

Abstract: A gas mixture containing phosphine and R.sub.1 R.sub.2 R.sub.3 In X R.sub.4 R.sub.5 R.sub.6 or R.sub.1 R.sub.2 In X R.sub.4 R.sub.5 where the Rs are alkyl groups is passed over a semiconductor substrate comprising indium and phosphorus so as to deposit a semiconductor material comprising indium and phosphorus, and the exposure of the substrate to phosphine is controlled to avoid or reduce transport of the substrate material.Thus, for example, indium phosphide may be grown onto corrugations in gallium indium arsenide phosphide, the corrugations being non-deformed during this growth. Such a growth step may be used in the production of distributed feedback semiconductor lasers operating near 1.55 .mu.m.

Abstract: A semiconductor device comprises a base semiconductor portion and, thereon, first and second elevated semiconductor portions separated by a channel. The uppermost surface of the first elevated semiconductor portion carries a metal electrical contact layer and the uppermost of the second a dielectric layer. The surfaces defining the channel are substantially free of metal and dielectric.The structure can be used in a ridge waveguide laser, the first elevated semiconductor portion constituting the ridge (7", 8").Distributed feedback corrugations may be incorporated in such devices (6), or in other ridge waveguide structures.