Publications Details
Dry etching of 3-5 nitrides
The chemical inertness and high bond strengths of the 3-5 nitrides lead to slower plasma etching rates than for more conventional 3-5 semiconductors under the same conditions. High ion density conditions (greater than 3 x 10(exp 11) cm(exp {minus}3)) such as those obtained in ECR or magnetron reactors produce etch rates up to an order of magnitude higher than for RIE, where the ion densities are in the 10(exp 9) cm(exp {minus}3) range. The authors have developed smooth anisotropic dry etches for GaN, InN, AlN and their alloys based on Cl2/CH4/H2/Ar, BCl3/Ar, Cl2/H2, Cl2/SF6, HBr/H2 and HI/H2 plasma chemistries achieving etch rates up to approx. 4,000 A/min at moderate dc bias voltages (less than or equal to {minus}150 V). Ion-induced damage in the nitrides appears to be less apparent than in other 3-5`s. One of the key remaining issues is the achievement of high selectivities for removal of one layer from another.