摘要:
The present invention provides a self-aligned laser structure that can be fabricated on a p-substrate and provides a means for limiting the leakage current thereby improving the overall efficiency of the structure. The waveguide laser structure comprises a first series of layers deposited in sequence upon a p-InP, p-GaAs or p-GaN substrate or other form of p-substrate, wherein these layers form the p-clad layer. An active layer is subsequently deposited upon this first series of layers. A blocking layer of insulating or semi-insulating material is deposited upon the active layer, wherein this blocking layer has a trench formed therein, wherein this semi-insulating layer or layers are epitaxially deposited. The blocking layer provides a means for limiting current flow therethrough, thereby reducing leakage current. Upon the blocking layer are deposited a second series of layers completing the laser structure, wherein this second series of layers form the n-clad layer. Since the n-clad layer contains more than one material, the structure provides lateral waveguiding. Upon the completion of the deposition of all of the layers, a positive electrode is formed on the bottom surface of the first series of layers and a negative electrode is formed on the top of the second series of layers.
摘要:
The present invention is a combination of in-situ etching with a grating mask pattern comprised only of semiconductor material, together with the fabrication of a protective layer beneath the semiconductor grating mask that protects the semiconductor material that readily oxidises. As such the present invention is based on a two-stage process. First the grating pattern is defined in a semiconductor material, wherein this pattern is called the semiconductor grating mask. The semiconductor grating mask sits on top of a layer of protective material, which in turn is on top of the semiconductor material that readily oxidises, wherein the protective layer prevents oxidation of the material below. The semiconductor structure is then moved to a reactor, where, in the second stage, the mask pattern is transferred into the underlying protective layer and the semiconductor material that readily oxidises, by in-situ etching. The grating is then overgrown in the same reactor without exposing the etched grating to the atmosphere. The overgrown material protects the underlying semiconductor material from oxidation when the structure is removed from the reactor.
摘要:
The present invention is a combination of in-situ etching using a grating mask that is formed in semiconductor material only and the subsequent overgrowth of additional semiconductor material to enclose the grating structure prior to exposure to the atmosphere and the contaminants therein. The present invention is based on a two-stage process. First the grating pattern is defined in a semiconductor material, which is the grating mask. This grating mask is created at a position above the material that is to ultimately contain the grating pattern. Upon the completion of the fabrication of the grating mask, the semiconductor structure is moved to a reactor, where in the second stage, the grating pattern defined by the grating mask is transferred into the underlying semiconductor layers by in-situ etching. The grating is subsequently overgrown with additional semiconductor material while in the same reactor, thereby not exposing the etched grating pattern to the atmosphere thereby reducing the contaminants in the grating structure of the semiconductor laser.