TMAH/KOH etch stop on SiO2

Hello,

 

            I have a question about using TMAH/KOH as a (poly)silicon blanket etch and its ability to stop on a thin doped oxide without attacking silicon below the doped oxide.

 

            Does TMAH/KOH etch n-doped oxide? If so are there ways around this? Insights would be appreciated. Is there a silicon etch which can stop on a thin n-doped SIO2?

 

            Thanks!

                        Arvind Kamath