Photo-Atomic Layer Etching of GaAs/AlGaAs Nanoheterostructures

High Resolution Image Download MS PowerPoint Slide Photo-atomic layer etching (photo-ALE) of GaAs and AlGaAs semiconductors was investigated in deionized H 2 O and aqueous solution of NH 4 OH under weak excitation conditions ( P ≈ 20 mW/cm 2 ). The process is based on digital photocorrosion in a processed solution and a negligible corrosion during the light-off phase employed for dissolution of the photocorrosion products. An inductively coupled plasma mass spectroscopy (ICP-MS) analysis revealed that photo-ALE of GaAs in an aqueous solution of NH 4 OH proceeds linearly with the number of reaction cycles, typically at ∼0.1 nm/cycle, and with the light-off phase as short as 22 s sufficient to entirely dissolve the photocorrosion products generated during a 3 s irradiation. In agreement with the ICP-MS data, the constant photo-ALE rates in NH 4 OH were also demonstrated in situ with the photoluminescence measurements. Our results suggest that the congruent decomposition of III–V materials and the etching of deep structures with atomic layer resolution could be facilitated by switching in situ between different etching environments.