Table 1.

Overview of etching experiments: date of experiment, stoichiometric concentration of HF, mean temperature during the etching process, etching velocity at zero field and experimental normalized first-order coefficient. The error estimates of concentration values given in the second column consider errors of volume measurements and a possible error due to evaporation of the stock solution. This evaporation error was estimated comparing etching rates measured with undiluted 40% acid measured in October 2008 and July 2009, and the estimate was δc HF/c HF≈6×10−4 month−1.

experimentconcentration (moll−1)T (°C)V (0) (nm s−1)α (nm V−1)
13 Nov 200711.40±3.8%23.82.9576±0.00091.596±0.045
22 Apr 200811.40±1.6%24.3952.9771±0.00091.567±0.011
13 May 200811.40±1.7%17.4202.085±0.0011.532±0.019
9 Oct 20089.54±2.3%20.7001.8676±0.00051.622±0.018
20 Oct 200822.79±0.7%21.40011.4340±0.00091.259±0.003