Chemistry Reference
In-Depth Information
Figure 7.19 shows the effect of concentration in solutions
on the etch rate of silicon.
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The etch rate increases with increasing con-
centration and reaches saturation at a certain concentration. The saturation etch rate
decreases with increasing
concentration. Figure 7.20 shows that the saturation
concentration, reaching a limiting value of
etch rate is inversely proportional to
about at high concentrations. According to Fig. 7.18 the silicon surface in the
solutions in Figs. 7.19 and 7.20 is passivated, implying that the etch rates shown in
Figs. 7.19 and 7.20 are in essence the etch rates of the passive silicon oxide film.
Formation of pyramidal hillocks bounded by (111) crystal planes on the (100)
solutions for all concentrations, temperatures, stirring
wafer is a problem in
