Abstract: Composite substrate for a waveguide for RF signals having a signal frequency, wherein said composite substrate comprises at least a first layer of dielectric material and a second layer of dielectric material, and at least one conductor layer of an electrically conductive material arranged between said first layer and said second layer, wherein a layer thickness of said at least one conductor layer is smaller than about 120 percent of a skin depth of said RF signals within said electrically conductive material of said conductor layer.

Abstract: Composite substrate (1300; CS) for radio frequency, RF, signals comprising at least a first layer (1310; 1310a) of di-electric material and a second layer (1320; 1320a) of dielectric material, and at least one conductor layer (1330; 1330a) of an electrically conductive material arranged between said first layer (1310; 1310a) and said second layer (1320; 1320a), wherein said first layer (1310; 310a) and said second layer (1320; 1320a) and said conductor layer (1330; 1330a) each comprise optically transparent material.

Abstract: Composite substrate for a waveguide for RF signals having a signal frequency, wherein said composite substrate comprises at least a first layer of dielectric material and a second layer of dielectric material, and at least one conductor layer of an electrically conductive material arranged between said first layer and said second layer, wherein a layer thickness of said at least one conductor layer is smaller than about 120 percent of a skin depth of said RF signals within said electrically conductive material of said conductor layer.

Abstract: A method for fabricating a bipolar transistor includes forming a vertical sequence of semiconductor layers, forming an implant mask on the last formed semiconductor layer, and implanting dopant ions into a portion of one or more of the semiconductor layers. The sequence of semiconductor layers includes a collector layer, a base layer that is in contact with the collector layer, and an emitter layer that is in contact with the base layer. The implanting uses a process in which the implant mask stops dopant ions from penetrating into a portion of the sequence of layers.

Abstract: A method for fabricating a bipolar transistor includes forming collector, base, and emitter semiconductor layers on a substrate such that the layers form a vertical sequence with respect to an adjacent surface of the substrate. The method includes etching away a portion of a top one of the semiconductor layers to expose a portion of the base semiconductor layer and then, growing semiconductor on the exposed portion of the base layer. The top one of the semiconductor layers is the layer of the sequence that is located farthest from the substrate. The growing causes grown semiconductor to laterally surround a vertical portion of the top one of the semiconductor layers.

Abstract: A method for fabricating a bipolar transistor includes forming a vertical sequence of semiconductor layers, forming an implant mask on the last formed semiconductor layer, and implanting dopant ions into a portion of one or more of the semiconductor layers. The sequence of semiconductor layers includes a collector layer, a base layer that is in contact with the collector layer, and an emitter layer that is in contact with the base layer. The implanting uses a process in which the implant mask stops dopant ions from penetrating into a portion of the sequence of layers.

Abstract: A method for fabricating a bipolar transistor includes forming a vertical sequence of semiconductor layers, forming an implant mask on the last formed semiconductor layer, and implanting dopant ions into a portion of one or more of the semiconductor layers. The sequence of semiconductor layers includes a collector layer, a base layer that is in contact with the collector layer, and an emitter layer that is in contact with the base layer. The implanting uses a process in which the implant mask stops dopant ions from penetrating into a portion of the sequence of layers.

Abstract: A method of fabricating a III-V heterostructure semiconductor device. The method includes the steps of forming at least one conductive post overlying a semiconductor region to form a structure, encapsulating the structure and the conductive post to form a planarized cured passivation layer, and exposing the conductive post through the planarized cured passivation layer to form the semiconductor device.

Abstract: A method for fabricating a bipolar transistor includes forming a vertical sequence of semiconductor layers, forming an implant mask on the last formed semiconductor layer, and implanting dopant ions into a portion of one or more of the semiconductor layers. The sequence of semiconductor layers includes a collector layer, a base layer that is in contact with the collector layer, and an emitter layer that is in contact with the base layer. The implanting uses a process in which the implant mask stops dopant ions from penetrating into a portion of the sequence of layers.

Abstract: The specification describes a lithographic technique in which alignment marks are defined in a first semiconductor layer and the alignment marks are then covered with a protective SiO2 layer. After subsequent semiconductor layer growth steps, which selectively deposit on the former semiconductor layer but not on the protective layer, the alignment marks remain undistorted and visible to the exposure tool for subsequent processing.

Abstract: The specification describes a metal contact material optimized for diffused contacts to the buried emitter-base junction in DHBT devices. The metal contact material is a multilayer structure of Pd--Pt--Au which gives the required critical diffusion properties for low resistance contacts to the buried base layer without shorting to the collector layer.

Abstract: The specification describes a trilevel resist technique for defining metallization patterns by lift-off. The trilevel resist comprises two standard photoresist levels separated by a thin silicon oxide layer with approximate composition SiO.sub.2.

Abstract: The specification describes a photolithography process using multiple exposures to form z-dimension patterns. Multiple exposures at different thickness levels are made using photomasks aligned with a latent image of alignment marks formed during the first exposure. The latent image is visible to the alignment system of commercial steppers.

Abstract: The specification describes a photolithography process using multiple exposures to form z-dimension patterns. Multiple exposures at different thickness levels are made using photomasks aligned with a latent image of alignment marks formed during the first exposure. The latent image is visible to the alignment system of commercial steppers.

Abstract: The specification describes a technique for repairing wafer fractures that occur during wafer fabrication. The fractured pieces are joined edge-to-edge at the fracture line and bonded with epoxy adhesive. The method succeeds because the dimensions of the fracture line after bonding is within the reregistration tolerance of commercial step-and-repeat cameras and the reregistration capability of the camera allows normal exposure of sites that do not intersect the fracture line.

Abstract: The specification describes a metal contact material optimized for diffused contacts to the buried emitter-base junction in DHBT devices. The metal contact material is a multilayer structure of Pd-Pt-Au which gives the required critical diffusion properties for low resistance contacts to the buried base layer without shorting to the collector layer.