Selective and non-selective etching of GaN, AlGaN, and AlN using an inductively coupled plasma

The etching behavior of gallium nitride (GaN) has been systematically examined in an inductively coupled plasma (ICP) using Cl ₂ and Ar as the reagents. Design of experiments (DOE) software was used to optimize the etch rate as well as determine any interactions between the parameters (ICP power, DC bias, and pressure). Interactions were found between the ICP power and pressure and also between the ICP power and DC bias. There were no interactions between the DC bias and pressure. Selective etching of GaN relative to AlN and Al_0.28Ga_0.72N was achieved at low DC biases. At -20 V, the GaN etch rates were 38 times greater than AlN and a factor of 10 greater than Al_0.28Ga_0.72N