Study On Micro/Nanofabrication By Friction-Induced Selective Etching Combiend With H₂SO₄Solution On Ga/As Surface

Due to its direct bandgap and high electron mobility, gallium arsenide (GaAs) has become one of the most widely used compound semiconductor materials. GaAs-based photovoltaic, microwave, laser and other components have great application value and market potential both in commercial and military application. However, nanofabrication is the bridge of GaAs device to application. At present, the nanofabrication field shows the features of diversity. Kinds of nanofabrication technology have been reported to produce GaAs nano devices, such as optical lithography, nanoimprint lithography, focused ion/electron beam, direct machining and local anodic oxidation, etc. However, each of them has its limitation and one kind of method is difficult to adapt to a variety of nanofabrication requirements. Therefore, it is of significance to develop new nanofabrication method on GaAs surface.This thesis firstly investigated the generation process of the friction-induced scratches through a nanoscratch tester. After carefully select the etchant to realize the post-etching of scratched GaAs surface, the effect of the applied normal load and etching period on the formation of nanostructure was studied. Secondly, the fabrication mechanism was discussed based on the detection of X-ray photoelectron spectrum and Raman spectrum on the GaAs surfaces. Finally, through the optimization of fabrication parameters, various nanostructures were fabricated on the GaAs surface and the friction-induced selective etching method was proposed. The main experimental results and conclusions were summarized in the following.1. A friction-induced selective etching method was proposed to produce nanostructures on GaAs surface. Without any resist mask, the nanofabrication can be achieved by scratching and post-etching in sulfuric acid solution.2. The generation process of the friction-induced scratches on GaAs surface was investigated. The sulfuric acid solution was selected to realize the post-etching of scratched GaAs surface. The effect of the applied normal load and etching period on the fabrication of the nanostructure was studied. Results showed that the height of the nanostructure increased with the normal load or the etching period.3. The fabrication mechanism of GaAs nanostructures was discussed based on the detection of XPS and Raman spectrum on the scratched GaAs surfaces. Results demonstrated that residual compressive stress and lattice densification were probably the main reason for selective etching, which eventually led to the formation of protrusive nanostructures on the scratched GaAs surface.4. Combined with the proposed method and a homemade multi-probe instrument, the controllable fabrication of large-area texture pattern on GaAs surface was successfully realized.