New Restricted Contact LEDs Using a Schottky Barrier

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Abstract
High radiance LEDs for optical communications require a small light emitting region to efficiently couple the emitted light into the optical fiber. The small light emitting region is generally accomplished by restricting the electrical contact on one surface of the device and isolating the remaining portions of the semiconductor surface from the conducting heatsink using a dielectric layer. In this paper, planar restricted contact LEDs, in which electrical isolation is achieved with a metal layer that forms a high resistance or non-ohmic contact (Schottky barrier) to the semiconductor, are demonstrated in the GaAlAs and InGaAsP/InP materials systems. These LEDs show comparable I-V characteristics and current restriction as devices fabricated with dielectric isolation. This new method of electrical isolation simplifies the fabrication procedure by eliminating the need for dielectric deposition and photolithography. Experiments to determine the long term reliability of these devices is in progress.