Highly-selective dry etching of InAlAs over InGaAs assisted by ArF excimerlaser with Cl-2 gas

Highly selective etching of InAlAs over InGaAs was observed by irradiation with a 193-nm ArF excimer laser in a Cl-2 atmosphere. The etching rate of I nAlAs relative to that of InGaAs increased as the laser fluence decreased a nd the Cl-2 pressure increased, and the highest observed etching rate ratio exceeded 70. The result was compared with the case of etching with HBr gas , where no enhancement of InAlAs etching was observed. It is speculated tha t the very fast InAlAs etching rate is due to the fast Al reaction and deso rption, which introduces new reactive sites on the surface.