High-Rate GaAs Epitaxial Lift-Off Technique for Optoelectronic Integrated Circuits

In the epitaxial lift-off (ELO) technique, where a GaAs device structure is lifted off from a GaAs substrate using selective wet etching of an AlAs release layer, the etching rate of the AlAs layer is increased by a factor of ~8 by raising the etchant temperature to 40° C and adding a surfactant and an antifoaming agent to the etching solution. The mechanism of the high-rate lift-off process is discussed based on the solubility and the diffusion coefficient of the etching product ( H2) in the etching solution. Photoluminescence measurement results show that the quality of the GaAs film is not degraded by the high-rate lift-off process. A high-rate lift-off technique for large-diameter wafers is proposed.