Patent application number | Description | Published |
20090020782 | Avalanche Photodiode With Edge Breakdown Suppression - The invention relates to an avalanche photodiode having enhanced gain uniformity enabled by a tailored diffused p-n junction profile. The tailoring is achieved by a two stage doping process incorporating a solid source diffusion in combination with conventional gas source diffusion. The solid source diffusion material is selected for its solubility to the dopant compared to the solubility of the multiplication layer to dopant. The solid source has a diameter between the first and second diffusion windows. Thus, there are three distinct diffusion regions during the second diffusion. The dopant in the multiplication layer at the edge region, the dopant from the solid source material with a relatively higher dopant concentration (limited by the solubility of the dopant in the solid source material) at the intermediate region, and the central region exposed to an infinite diffusion source from the solid source material as it is continually charged with new dopant from the external gas source. The result is that both the dopant concentration and the diffusion depth decrease gradually from the center to the edge of the device. This tailored diffusion profile enables control of the electric field distribution such that edge breakdown is suppressed. | 01-22-2009 |
20090020841 | Mesa-Type Photodetectors With Lateral Diffusion Junctions - The present invention relates to a stable mesa-type photodetector with lateral diffusion junctions. The invention has found that without resorting to the complicated regrowth approach, a simple Zn diffusion process can be used to create high-quality semiconductor junction interfaces at the exposed critical surface or to terminate the narrow-bandgap photon absorption layers. The invention converts the epi material layers near or at the vicinity of the etched mesa trench or etched mesa steps into a different dopant type through impurity diffusion process. Preferably the diffused surfaces are treated with a subsequent surface passivation. This invention can be applied to both top-illuminating and bottom-illuminating configurations. | 01-22-2009 |
20090121305 | Front-Illuminated Avalanche Photodiode - The present invention provides a front-illuminated avalanche photodiode (APD) with improved intrinsic responsivity, as well as a method of fabricating such a front-illuminated APD. The front-illuminated APD comprises an APD body of semiconductor material, which includes a substrate and a layer stack disposed on a front surface of the substrate. The layer stack includes an absorption layer, a multiplication layer, and a field-control layer. Advantageously, a back surface of the APD body is mechanically and chemically polished, and a reflector having a reflectance of greater than 90% at the absorption wavelength band is disposed on the back surface of the APD body. Thus, incident light that is not absorbed in a first pass through the absorption layer is reflected by the reflector for a second pass through the absorption layer, increasing the intrinsic responsivity of the front-illuminated APD. | 05-14-2009 |
20090242933 | Semiconductor Photodiode And Method Of Manufacture Thereof - A method of manufacture of an avalanche photodiode involving a step of making a recess in a top window layer of an avalanche photodiode layer stack, such that a wall surrounding the recess runs smoothly and gradually from the level of the recess to the level of the window layer. Further, diffusing a dopant over the entire window layer area so as to form a p-n junction at the bottom of the recess, and providing a first electrical isolation region around the recess by buried ion implantation or wet oxidation in order to limit the flow of electrical current to the p-n junction. Forming an isolation trench around the photodiode and a second electrical isolation region by ion implantation into the trench such that the second electrical isolation region runs through the absorption layer of the photodiode. | 10-01-2009 |
20100181651 | SEALED SEMICONDUCTOR DEVICE - A sealed semiconductor device having reduced delamination of the sealing layer in high temperature, high humidity conditions is disclosed. The semiconductor device includes a substrate and a stack of device layers on the substrate sealed with a sealing layer. The upper surface of a street area of the substrate is oxidized so that the oxidized region extends under the sealing layer. The presence of the oxidized region of the upper surface of the substrate helps reduce the delamination, because the oxidized surface does not react with water to the same extent as a non-oxidized surface. The semiconductor devices remain sealed after dicing through the street area because the oxidized surface does not delaminate. | 07-22-2010 |
20100301441 | PHOTODIODE WITH HIGH ESD THRESHOLD - A photodetector with an improved electrostatic discharge damage threshold is disclosed, suitable for applications in telecommunication systems operating at elevated data rates. The photodetector may be a PIN or an APD fabricated in the InP compound semiconductor system. The increased ESD damage threshold is achieved by reducing the ESD induced current density in the photodetector by a suitable widening of the contact at a critical location, increasing the series resistance and promoting lateral current spreading by means of a current spreading layer. | 12-02-2010 |
20120098615 | BROADBAND NON-COPLANAR FEEDTHROUGH - A high-speed feedthrough (HSFT) is disclosed for transmitting a signal having a highest frequency of at least 10 GHz between first and second locations separated by a vertical distance of at least approximately half of the shortest transmitted wavelength, and separated by a horizontal distance. A substrate structure includes multiple stacked layers. An RF transmission line is connected through the structure between the first and second locations for transmitting the signal. The RF transmission line comprises a series of sequentially connected horizontal conductors having lengths less than half of the effective wavelength and vertical conductors having heights less than one quarter of the effective wavelength, thereby spanning the horizontal and vertical distance between the two locations in a stairs-like shape through the structure's layers. Each conductor's geometry may deviate from standard 50 ohm buried strip lines and is optimized for complete 3-dimensional structure. | 04-26-2012 |
20130084075 | SUPER-CHANNEL ASSIGNMENT USING A FLEXIBLE GRID - A node is configured to receive an instruction to establish a channel having a bandwidth that corresponds to an operating spectrum an optical fiber; obtain information that identifies a channel spacing and a pointer that identifies where, within the spectrum, to establish bandwidth allocations; identify a group of bandwidth segments based on the spectrum and the channel spacing; and generate bit words that correspond to the bandwidth allocations, where the bit words includes bits that, when set to a value, cause sets of segments to be reserved within the spectrum, and where the sets of segments identify where the bandwidth allocations begin and end, within the spectrum, relative to the pointer. | 04-04-2013 |