ion implantation question

Hi all,

I am planning on doing phosphorous ion implantation this week at INNOViON in San Jose. This will be on an already-fabricated vertical pin structure. I was planning to deposit LPCVD oxide over my entire structure, then pattern and etch it to open up the n regions where I want the ions implanted.

Can anyone tell me how thick this oxide should be to prevent P doping in my p region? Your prompt responses are greatly appreciated, as this is a process I was planning on carrying out over the next day or two.

Thanks so much,
Stephanie