Effect of dry etching conditions on surface morphology and optical properties of GaN films in chlorine-based inductively coupled plasmas

The effects of dry etching conditions on surface morphology and optical properties of semiconducting gallium nitride (GaN) films was studied in chlorine based inductively coupled plasma (ICP) systems. Smooth morphology was seen upto 150W of ICP source power while rougher surfaces were produced on etching at high chuck powers due to increased ion bombardment. The lattice disorder and point defect density were lesser in ICP etching than in reactive ion etching (RIE). The decrease in intensity of band edge emission in as-grown n-GaN was inversely propotional to chuck power. A weak intensity of band edge was seen for p-GaN with the peak shifting to 460nm and increase in photoluminiscence intensity.