| 摘要 |
PURPOSE:To obtain a uniform and flat etching surface by adhering a mask having an etching hole to a semiconductor sample, stirring an etching soln. and controlling the etching rate at the circumferential edge of the sample facing the inside of the hole by utilizing the step of the hole. CONSTITUTION:The plate-shaped glass mask 1 opened with the hole having a suitable diameter is adhered to at least one surface of the GaAs semiconductor sample 2 and is dipped into the etching soln. consisting of, for example, H2 SO4:H2O2:H2O=3:1:1. The soln. 5 is stirred by driving a stirrer 7. A step is formed between the mask 1 and the sample 2 by providing some degree of thickness to the mask 1 so that the flow of the liquid at the boundary face of the mask 1 is retarded to decrease the etching rate at the circumferential edge part. The ordinary etching rate is maintained in the central part so that the uniform etching is eventually executed over the entire region. The film thickness of the sample 2 is observed by transmitting a white light source 3 through the sample 2. |
