Fabrication of microstructures on GaAs with pulsed electrochemical wet stamping

Fabrication of microstructures on gallium arsenide (GaAs) was investigated using electrochemical wet stamping (E-WETS) by limiting a selective anodic dissolution process in the contact area between a stamp and a GaAs substrate. The pre-patterned agarose stamp acts as a current flow and electrolyte channel between a working electrode and a counter electrode. A short potential pulse was applied to improve the precision as well as surface roughness of the fabricated microstructures on GaAs surfaces. The pulse width of 100 μs and pulse-to-pause ratio of 1:3 were selected as optimum machining parameters. Lateral deviation of the fabricated microstructures from those on the master was approximately 1.3%, and the electrochemical etch rate in 0.1 M HBr was approximately 40 μm/h. The results demonstrated that E-WETS was a promising approach to fabricate microstructures on GaAs with high accuracy and efficiency.