Hi, Thank you guys for replying to my previous mail. What iam trying to do was to make use of the silicon wafers with the grown oxide layer to fabricate deep v-grooves using KOH. As you all know that one micro thick is not sufficent enough to make deep grooves. I can go a head and change the mask to silicon nitride, but before doing that i wanted to know why can't we grow thicker oxide layers and use it for deeper grooves. I am trying to look for some books or papers that gives me some solid proof that i have change the my mask. If any of you guys can mention the books or papers that i am looking for would be really helpful and i would really appriciate for your help. Thank you all, Regards, Dhanamjaya R Guda