normally we will use thermally grown silicon dioxide as a masking layer for TMAH silicon etching .But can we use RF Sputtered sio2 as a masking layer for etching . I heard that sputterd sio2 having pores in the layer ,
Yes normally sputtered SiO2 layers will have some porosity. They are not so dense as a conventional thermally grown oxide layer on silicon, and hence sputtered layers are more prone to be attacked during etching.
K. Sreenivas
There is a solution if you must use the sputtered Sio2. Sputter say 100nm and then close the shutter and wait for 10-15 min and then sputter again another 100nm and so on. In this way the pin holes in the first layer would not be aligned with the next layer so by adding couple of layers you can have almost as good as grown Sio2 masking!
Hi,
You can obtain high density SiO2 films by sputtering by controlling the pressure. We have described it in J. Olivares, et all. IEEE Trans. Ultrason, Ferroelec., Freq. Control, 57, (2010) 23-29.
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