Optoelectronic semiconductor device having plural mesas
AssigneeU.S. Philips Corporation
InventorsPetrus J. A. Thijs, Aart Van Leerdam, Johannes J. M. Binsma
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AssigneeU.S. Philips Corporation
InventorsPetrus J. A. Thijs, Aart Van Leerdam, Johannes J. M. Binsma
Estimating the term…
Optoelectronic semiconductor devices including a semiconductor body with a semiconductor substrate and a substantially plane semiconductor layer structure of III-V semiconductor materials situated thereon, a mesa being formed at a surface of the semiconductor body by means of selective deposition and forming part of an optoelectronic element, are important components in optical communication and optical disc systems or bar code readers. The optoelectronic element often is a semiconductor diode laser, but may alternatively be, for example, a radiation guide. A disadvantage of the known devices is that parasitic deposition takes place next to the mesa during the selective deposition. In addition, the device often contains so-called cleavage steps near the mesa. Another disadvantage is that the height and flatness of the upper side of the mesa are not accurately controllable. According to the invention, a second mesa is present at at least two opposing sides of the mesa, separated from the first mesa by a groove, the surface area of the second mesa in plan view being much greater than the surface area of the first mesa, which second mesa is also formed by means of selective deposition and simultaneously with the first mesa. In this configuration, less parasitic deposition takes place than expected and there is less damage near the first mesa after cleaving. When the distance between the first mesa and the second mesa is chosen to be sufficiently small, it is also found that the flatness and height of the first mesa are accurately controllable.
An optoelectronic semiconductor device having an optoelectronic element comprising a semiconductor body provided with a semiconductor substrate and a substantially plane semiconductor layer structure of III-V semiconductor materials superimposed on said substrate, and a first mesa formed at a surface of said semiconductor body by means of selective deposition and forming part of said optoelectronic element, characterized in that a second mesa having two mesa portions is formed by means of selective deposition simultaneously with said first mesa, said two mesa portions being present at at least two opposing sides of said first mesa and having surface areas, which, seen in plan view, are greater than a surface area of said first mesa and are separated from said first mesa by grooves, and insulating layer portions beneath said grooves and extending laterally at least partially beneath said first and second mesas, each mesa portion having a constricted portion beneath said mesa and near its base, the lateral extent of said constricted portion being defined at least partly by at least one of said insulating layer portions.
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