Role of Ion Energy and Flux on Inductively Coupled Plasma Etch Damage in InGaN/GaN Multi Quantum Well Light Emitting Diodes

Abstract

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 Cl2/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 ∼300 eV. The current transport in the LEDs is dominated by generation-recombination and surface leakage components (ideality factor ≥2) in all cases.