SiO2 should make a good etch mask for Si. How deep does the Si have to
be etched? Also depends on the type of SiO2 - thermal, CVD etc..

On Mon, Jun 6, 2011 at 9:05 AM, Judith Linacero Blanco
 wrote:
> Hi all,
>
> Does anybody know how to etch Si with a SiO2 mask? Because I use 50sccm
> HBr, 30mT and 200W in the RIE system, but the selectivity isn't good.
> I only have 20nm of SiO2 to etch silicon.
>
> Thanks a lot,
> Judith