We wanted to test the effects of changing the substrate bias during the Si deposition step similar to what Dave Fang had done so many years ago. Attached is a couple of plots showing the effect of varying substrate bias on pore size and porosity. He used 15 nm thick a-Si and an anneal at…
We deposited a 20/60/20 nm OSO stack for an ellipsometry test. We decided to try annealing the un-patterned wafer in the RTP at 1050 C with no susceptor with a 100 C/s ramp for 60 s. The attached SEM images show pores forming. With these encouraging results, we are considering depositing 40, 50 and 60…
This is a continuation of earlier work showing 30-100-30 NSN x-sections where the Si layer thickness increases from ~92 nm before RTP to ~130 nm after RTP. Below are SEMs showing a ~50 nm thick a-Si film becoming a ~62 nm thick pnc-Si. (1000 C, 50 C/s, 60 s in susceptor, RTP after EDP etch) I…
Below are some SEM images of a burst 30-50-30 NSN membrane in a SEPCON pattern. Many similar chips failed at lower pressures, but this one survived to ~5-7 psi. (didn’t keep close track of the chips after they were burst, so I’m not sure which pressure this burst at, but it was within the 5-7…
Karl, Charles and I measured the burst pressure and permeance of some 30-50-30 and 30-100-30 NSN. Burst Pressure: The SEPCONs readily burst at pressures under 1 psi when the flow was directed from the backside of the chip through the membrane. The membranes were able to withstand higher pressures when the pressure was applied from…
Still trying to reproduce Joe’s large pore material on SEPCONs using NSN stacks. This post has data from two wafers with 30/50/30 and 30/100/30 NSN. RTP is 1000C 50C/s for 1min. Nitride is etched off by placing samples in 50% HF for 3.5 minutes. (~30s after that the films start to lift off) I start…
First things first, the desalting column is not intended to desalt. Apparently that’s just an old name that has carried over. The current purpose is to separate viruses from large debris after sonication. The sample in a buffer solution will be placed in the center of the cartridge and sonicated in the “glass bead pod”….
We are trying to reproduce the very small pores Joe created with 30/100/30 OSO and large pores created with 30/100/30 NSN using a SEPCON pattern. (Joe’s previous post.) We had a problem with several chips releasing from the center of the wafer prior to completely clearing all the features. In the future we will use…
INT received the first samples of their new cartridge design. The following slides were given to us by INT to provide some detail. The shorter cylinder on the left that is called the “glass bead pod” needs on filter fixed to the bottom. The taller cylinder is the “desalting chamber” and will require a filter…
Karl and I went to INT to meet with Mike Connolly and Rick Murante for preliminary discussions on the PFI project. Our role as proposed in the grant is to provide membranes capable of eliminating false positives by using ~20nm pnc-Si to reduce contamination. Here’s a link to an INT video showing their process and prototype. (4…