The chemical inertness and high bond strengths of the III-V nitrides l
ead to slower plasma etching rates than for more conventional III-V se
miconductors under the same conditions. High ion density conditions (>
3 x 10(11) cm(-3) ) such as those obtained in ECR or magnetron reactor
s produce etch rates up to an order of magnitude higher than for RIE,
where the ion densities are in the 10(9)cm(-3) range. We have develope
d smooth anisotropic dry etches for GaN, InN, AIN and their alloy base
d on Cl-2/CH4/H-2/Ar, BCl3/Ar, Cl-2/H-2, Cl-2/SF6, HBr/H-2 and HI/H-2
plasma chemistries achieving etch rates up to similar to 4000 Angstrom
/min at moderate d.c. bias voltages (less than or equal to -150 V). Io
n-induced damage in the nitrides appears to be less apparent than in o
ther III-Vs. One of the key remaining issues is the achievement of hig
h selectivities for removal of one layer from another. (C) 1997 Elsevi
er Science Ltd.