For a detailed study of the microstructures and grain boundaries of the matrix or reinforcement, the polished sample is to be etched using some suitable etching agent.
Subsequently, the barrier layer has to be etched away using chemical etching which often leads to the non-uniform widening of pores at the bottom.
Therefore, the amorphous and deformed silicon is relatively difficulty to be etched and can act as an etching mask of the Si(100) surface in KOH solution.
The etching process comprises two steps, which are [10] (1) the diffusion of the chemical etching solution to the surface of the material that is to be etched and (2) the reaction of the chemical etching solution with the materials.
However, when the specimen temperature was lower than 100 °C with H2 or CH4 gas added plasma condition, a-Si layer was not etched at all, but in the range of 100 140 °C of specimen temperature, the a-Si layer started to be etched while the influence of the specimen temperature on etching of a-Si was ignorable in that temperature range.
Aluminum needs to be etched first (ie. a thin coat of self-etching primer) before the regular paint primer.
With electron-beam etching, past systems have required millions of circuits to be etched, in effect, a line at a time.
In fact, n-doped Si was found to be etched faster than p-doped Si [17, 23], and the etching rate decreases with increasing dopant concentration for both n- and p-doped Si [11, 17, 24].
All grain boundaries are prone to be etched to a certain threshold, that is defined by the deposition conditions and etching solution.
While this might suggest, at least in the system they considered, that the dependence of etching rate on surface energy is weak, it should also be noted that the substrate to be etched was initially smooth.
Today, they are small enough to be etched into the side of a computer chip.
