2.5 λ microcavity InGaN light-emitting diodes fabricated by a selective dry-etch thinning process

The authors report on InGaN microcavity light-emitting diodes with an effective thickness of ∼450nm at the emission wavelength of ∼415nm. The starting material for the flip-chip laser lift-off device is a structure with an active region embedding six InGaN∕GaN quantum wells, ∼60-nm-thick AlGaN, and a GaN template grown on a c-plane sapphire substrate. High-precision control of the final microcavity thickness was facilitated by SF6-based selective inductively coupled plasma etching on the flipped material with an etch rate of ⩾5:1 for GaN:AlxGa1−xN, where x⩾0.15. Pronounced microcavity effects were observed by angular measurements, in agreement with the theoretical cavity-mode dispersion characteristics.