Production from 2.8.2008
We’ve got pores! Unfortunately, we are still being plagued by an unknown contamination that seems to be “eating” away at our membranes. This would explain why we’ve been having a hard time separating.
We also observe a strong radial dependence in porosity AND size with these RT deposited films. In the past it was limited to a porosity variation, only.
Wafer 393 – RT deposition 40/15/40 stack
(0,2) – 30kx
(2,0) – 30kx
(0,4) – 30kx
(4,0) – 30kx
To combat these issues, we propose:
- Create a new silicon etch cell which contains no copper-containing braze, zinc-containing ceramic compound. The new etch cell will also accommodate a larger volume of EDP which will help with the supersaturation of silicon in solution, hopefully reducing the amount of silicon deposit condensing on the membranes. All the materials for this new cell are ready, and the plans are being discussed with Paul this week.
- Start depositing at a high temperature again. Paul said the new heater would be ready by the end of this week.
- We’ve RTPed a 4″ wafer on top of a 6″ substrate which should help with the temperature non-uniformity across the RTP. TEM images will be available, soon.
Great looking membranes! Decent porosity and smaller pores with sharp cut-offs again. Meliora!
Great looking TEMs – yes. Great looking membranes – no. These are full of pinholes and that crazy particulate attack. It is good to see that the pores are getting smaller, though.
Dave – the last two histograms are too similar to be real. Please check and make sure that two different image were analyzed. Thanks!!
histograms fixed.
I lied. These pores are still close to 40 nm; used the 50kx instead of the 30kx calibration originally. Sorry.