Role of ion energy and flux on inductively coupled plasma etch damage in InGaN/GaN multi quantum well light emitting diodes

The effect of inductive coupled plasma (ICP) etching of GaN light-emitting diodes (LEDs) on the device performance was investigated. InGaN/GaN multi-quantum well LEDs with emission wavelengths 420 nm were fabricated using Cl(2)/Ar ICP etching to form the mesa for the n-contact. Different rf chuck powers (controlling incident ion energy) and source powers (controlling ion flux) were used to examine their effect on junction leakage current. At high ion fluxes (source powers > 500 W), the junctions were very heavily damaged. The forward turn-on voltage was increased by using higher ion energies from 4.55 V for 120 eV ion energy to 5.1 V for 300 eV. The reverse bias current was much less sensitive to the ion energy during plasma etching and increased only above an average ion energy of similar to 300eV. The current transport in the LEDs is dominated by generation-recombination and surface leakage components (ideality factor >= 2) in all cases.