Low-cost optical sub-assemblies for metro access applications
The fiber optic communications industry is experiencing significant change as datacom 10 Gb/s Ethernet (10 GbE) networks merge with telecom SONET 10G networks in the drive to reach metro access applications. Lower data rate (1G Ethernet, 1G and 2G fiber channel, and SONET OC-48) applications have already merged to some extent as various versions are available within the SFF or SFP standard transceiver form factors. Traditional 10 Gb/s optical subassemblies (OSAs), developed for SONET OC-192 applications, used variations of the expensive butterfly type package. However, smaller form factor modules (such as the XFP that uses SFF optical connectors and LC duplex optical connectors) require much smaller OSAs. To meet the size limitation of packaging 10G OSAs into the XFP transceiver and also meet the 10 GbE market challenge of providing low-cost solutions, new 10 Gb/s OSA components are needed.
Silicon optical bench for high-speed optical subassemblies [optical receiver]
A passively aligned, flip-chip receiver optical subassembly (ROSA) was developed. The design features a silicon v-groove with a metallized reflector and a photodiode with an offset active area. This design minimizes the optical path length, allowing for much smaller photodetector areas than those used in previous designs. Excellent performance in terms of coupling efficiency, small signal bandwidth and 10 Gb/s eye diagrams for detectors as small as 20 /spl mu/m in diameter are described. Mechanical features on the bench included special structures for optical underfill, fiber attachment and strain relief.
Water‐Induced Corrosion of Materials Used for Semiconductor Passivation
The authors show for the first time that both chemical corrosion and electrochemical corrosion of silicon-based films does occur, and that this corrosion leads to device failure. Chemical corrosion is the dominate failure mechanism when devices are aged between 500 and 1,500 h. Typically, a small number of failures are found as a result of chemical corrosion. However, if the devices are improperly packaged, then this mechanism can be responsible for most if not all failures. The mechanism is characterized by an activation energy between 0.6 and 1.0 eV depending on the passivation stoichiometry. Electrochemical corrosion dominates long term failure and is strongly dependent upon the resistivity of the passivation. They found that the median lifetime could vary by two orders of magnitude depending on the film resistivity. Because of this large variation in median lifetimes, it is important to characterize the resistivity of the passivation films used for given technologies, remembering, of course, that the resistivity is strongly dependent on film stoichiometry, applied field, and local geometry.