Fem Analysis And Experimental Research Of Confined Etchant Layer Technique On GaAs Surface

Gallium arsenide(GaAs) is a kind of III-V semiconductor material which has a wide application. Micro-nano processing methods are usually unable to satisfy the processing of high resolution, high machining efficiency at the same time. Confined etchant layer technique as a new type of micro electrochemical machining method can meet the requirements mentioned above which has a great development potential.In this thesis, we studied CELT based on the finite element method. First we introduced the setting of the model, the theoretical background of the key parameters setting for the static CELT. Based on these work, the three-dimensional geometrical model of the static CELT was built, and finite element method was used to study the influence of the electrode geometry and the working distance on the concentration distribution in solution. The three-dimensional geometrical model of the dynamic CELT was built, and finite element method was used to study the influence of the electrode geometry, the working distance and the forced convection on the concentration distribution in solution.We studied the computing methods of the three-dimensional static CELT workpiece surface profile and verified the correctness of the method by the comparison between the simulation and experimental results reported in literature. To study the influence of the solution concentration, the solution proportion, the working distance, the electrode geometry and the processing time on diffusion and etching, particular simulations and analysis of static CELT was carried out.We studied the computing methods of the three-dimensional dynamic CELT workpiece surface profile. Using this method, simulation and analysis of the dynamic CELT was carried out, and we studied the influence of the solution concentration, the solution proportion, the working distance, the electrode geometry, the translational velocity, the rotational velocity, the turning radius and the processing time on diffusion and etching. Besides, through the simulation and analysis of the technological parameter in smooth processing, we studied the selection method for the solution concentration, the working distance, and the transverse feed.The CELT processing platform was designed and built, then we carried out CELT experiment and analyzed the etching results. The conclusion is that the static and dynamic etching on GaAs wafer can be prepared on the CELT processing instrument; The correctness of simulation results are proved qualitatively by comparison between experimental and simulation results.