GaN etch enhancement in inductively coupled BCl3 plasma with the addition of N2 and SF6 gas

Abstract

Etching of GaN using BCl3/N2, BCl3/SF6 and BCl3 by inductively coupled plasma (ICP) was performed and the effects of N2 and SF6 were examined using optical emission spectroscopy. With the addition of 40% N2 and 20% SF6 to BCl3, the etch rate of GaN was increased from 600 to 2800 and 2000 Å min−1 at 700 W ICP power, respectively. There was a clear relationship between the increase of GaN etch rate and reactive Cl with the addition of N2 and SF6 gas to BCl3. In addition, B emission intensity was increased also with Cl emission intensity and negligible BN emission was observed. This means that N2 and SF6 reduce the recombination probability of B and reactive Cl and result in higher concentration of reactive Cl and higher etch rate with the addition N2 and SF6 to BCl3 plasma.