Hallo David!
On 4/26/19 2:43 PM, David Lanzendörfer wrote:
Hi everyone So this week was pretty productive. It turns out, that RCA-1 at room temperature removes all the unreacted material perfectly within 20 minutes. No more halo this time, anywhere and no more unwanted conductive residue.
However: The polysilicon expands also laterally when reacted with titanium, which leads to a short circuit with the junctions. In order to prevent it, we've prepared a second sample wafer, where we will deposit around 20 nm of silicon nitride and form the spacers using a dry etcher.
Awesome! Thanks for your great work!
For people not owning a dry etcher (wet-etching-only folks) an additional mask will be required unfortunately, in order to cover the poly silicon and silicon first with a thin LTO layer and then opening the LTO up only above the poly and the to-be-reacted junction areas.
)-:
Unfortunately, next week there is a public holiday (1st May) and Thursday and Friday the stepper aligner is offline, so the opening holes and interconnect tests with switching report can only be done, Monday in two weeks... :-/
We already got so far. Keep going! I'm very curios to get more informations from the clean room.
Best Regards, Hagen Sankowski