No abstract

A structure for high brightness light-emitting diodes (LEDs) is demonstrated. A distributed Bragg reflector (DBR) is used to enhance the quantum efficiency of the LEDs. This unique DBR uses a composite structure that consists of two DBRs to provide both high reflectivity and wide angle reflection. For 590 nm (amber range) AlGaInP LEDs, the quantum efficiency is increased to 5.05% by using this composite DBR structure. This result is much better than those obtained from conventional DBRs, and is comparable to that of wafer bonded AlGaInP LEDs.

A novel multipoint monitoring system with a plastic-optical-fiber-bundle (POFB) based feature is presented for measuring photoresist dissolution rate. The POFB that consists of different structures at probing and receiving ends excludes the needs of beam splitters and mirrors. The mean value and the standard deviation on thickness of AZ-1350 photoresist film coated on silicon wafer were measured to be 1850 and 26 nm, respectively. A measuring error of less than 1.5% is reported by using this system. The thickness data of photoresist films on Si wafer measured by this system are in good agreement with those measured by ellipsometry. This system exhibits superiorities of more flexible structures, easier operating procedures, and lower cost in comparison with conventional ones.