Resist-Free Direct Stamp Imprinting of GaAs via Metal-Assisted Chemical Etching.

We introduce a method for the direct imprinting of GaAs substrates using wet-chemical stamping. The predefined patterns on the stamps etch the GaAs substrates via metal-assisted chemical etching. This is a resist-free method in which the stamp and the GaAs substrate are directly pressed together. Imprinting and etching occur concurrently until the stamp is released from the substrate. The stamp imprinting results in a three-dimensional anisotropic etching profile and does not impair the semiconductor crystallinity in the wet-chemical bath. Hole, trench, and complex patterns can be imprinted on the GaAs substrate after stamping with pillar, fin, and letter shapes. In addition, we demonstrate the formation of sub-100 nm trench patterns on GaAs through a single-step stamping process. Consecutive imprinting using a single stamp is possible, demonstrating the recyclability of the stamp, which can be used more than 10 times. The greatest benefit of this technique is the simple method of patterning by integrating the lithographic and etching processes, making this a high-throughput and low-cost technique.