TiN Enhancement of Output Performance for Light-Emitting Diodes under High Injection Current

Thin titanium nitride (TiN) films with low sheet resistance and high transparency are deposited on AlGaInP light-emitting diodes (LEDs) to improve light extraction from the LED surface. Comparison test devices are fabricated both with and without TiN spreading layers. At a high injection current, the TiN film spreads the current over a large area of the device and improves the distribution of light emission. Therefore, the current crowding effect is reduced and light-output power is increased. Background theory is discussed and experimental results are presented. It is shown by theory and experiment that the transparent conducting TiN films can be used as inexpensive, easily implemented current-spreading layers for improved global reliability and efficiency of AlGaInP LEDs.