In situ monitoring of GaN reactive ion etching by optical emission spectroscopy

The optical emission during GaN reactive ion etching (RIE) using Cl-2 plasm a was monitored in situ by optical emission spectroscopy (OES). The optical emission intensity of atomic Ga is in proportion to the etch rate, and the time-integrated values of the optical emission intensities from atomic Ga and molecular N-2 are proportionally correlated to the etched volumes of Ga N. It is found that monitoring of the Ga and N-2 optical emissions allows i n situ control of the etching depth of GaN even if the etch rate fluctuates during the etching process.