Analysis of the strain dependent acidic etch rate on diamond wire sawn silicon wafer
- Processing of silicon in microelectronics, photovoltaics and micromechanics includes thermal and mechanical processing that can lead to a change in the silicon lattice, such as phase transitions or lattice deformations which have a crucial impact on the mechanical properties and the chemical resistance of silicon. In this work the correlation between lattice deformations and the etching of silicon using a HF/HNO3 solution is investigated. Here we use Raman microscopy to quantify and qualify strain on mechanically treated silicon, as well as confocal microscopy to measure the topography and to calculate the local etch rate. Additionally, a thermal treatment is used to selectively relax strained silicon for better understanding the effect of a selective kind of strain on the etching mechanism. Our results show that only in tensile strained areas, with a deformation strength of at least 2 cm-1, small cracks are formed within the first 10 seconds of etching. After all strained silicon is etched away the etch process mainly depends on theProcessing of silicon in microelectronics, photovoltaics and micromechanics includes thermal and mechanical processing that can lead to a change in the silicon lattice, such as phase transitions or lattice deformations which have a crucial impact on the mechanical properties and the chemical resistance of silicon. In this work the correlation between lattice deformations and the etching of silicon using a HF/HNO3 solution is investigated. Here we use Raman microscopy to quantify and qualify strain on mechanically treated silicon, as well as confocal microscopy to measure the topography and to calculate the local etch rate. Additionally, a thermal treatment is used to selectively relax strained silicon for better understanding the effect of a selective kind of strain on the etching mechanism. Our results show that only in tensile strained areas, with a deformation strength of at least 2 cm-1, small cracks are formed within the first 10 seconds of etching. After all strained silicon is etched away the etch process mainly depends on the resulting surface texture. The enhanced oxidation rate of tensile strained silicon by nitric acid is also shown exemplary by the surface modification using nitric acid and trichloro(octyl)silane.…
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