Improvement Of External Quantum Efficiency Of AlGaInP-based LEDs By Surface Roughening

In view of the current AlGaInP LEDs the external quantum efficiency has been low-all the times, this paper using the method of surface roughening to rough the traditional and new wafer-bonding AlGaInP LEDs.This paper made a traditional and new wafer-bonding AlGaInP red LEDs, detailly analyzed the characteristics of each roughening layer. For traditional AlGaInP LEDs the paper designed the wet chemical roughening by using of H3PO4/HNO3mixture and H2O2/HF mixture respectively, and with ICP for dry roughening, combined wet and dry methods to rough the three schemes. For wafer-bonding AlGaInP the paper researched the amount of Al in roughing layer (AlxGa1-x)0.5In0.5P’s influence on roughing process, the paper designed wet chemical roughening by using of HCl/H3PO4mixture for wafer-bonding AlGaInP LEDs.After testing the produced device the results showed that, for traditional AlGaInP LEDs. the external quantum efficiency increased by8.3%after wet roughening when using HNO3/HF mixture, when using ICP etching the external quantum efficiency increased by11.7%. the combine of wet and dry methods could increase external quantum efficiency by20.8%. It’s most suitable for roughening surface when the the Al composition is0.4for wafer-bonding AlGaInP LEDs. the HCl/H3PO4mixture method could increase external quantum efficiency by79.3%at most.