Effect of Aluminum Wet Etching on GaAs and Poly-DiMethylSiloxane Substrate: Surface Morphology and Topography Analysis

摘要

Interconnects are the spine of a circuit or a device and eventually, aluminum (Al) are commonly utilized for them. This argument motivates us to pursue this research. As a circuit or a device can be formed on a single crystal or on a polymer which depends on the application requirements.Thus, for observing the impact of the Al wet etching over single crystal (i.e., GaAs) and polymer (i.e., PDMS), two variety of samples are utilized, namely Al/GaAs (001), and Al/PDMS heterostructures. Thermal evaporation is used for depositing 400 nm Al film on GaAs and PDMS substrate, respectively.FE-SEM and AFM characterization has been carried out to measure the undercut edge, and surface roughness due to wet etching. The wet chemical etching of Al has been performed in a mixture of H_(3)PO_(4):C_(2)H_(4)O_(2):HNO_(3):H_(2)O(3:1:3:1) for 2 minutes. After etching, surprisingly, GaAs has been found rougher than the PDMS sample. However, before etching, PDMS was rougher than GaAs. This result shows the better adhesion of Al on GaAs than on PDMS.