Sarah, Tejas, and I bought some “Invitrogen Ultrapure DI water” from the medical center to see if we would find a different permeability using the clean water vs the water from the Barnstead. Sarah and I repeated our permeability tests but made sure to measure the flow rate for the first 100 uL. We got…
Sarah and I did some more gold separations with 10, 20, 40, 50, 60, 80 and 100 nm Au particles. We used the “clean” water purchased from the medical center. Same as last time, we diluted the “as-bought” gold 3 parts to 1 and loaded each cell with 300 uL before pressurizing at 5 psi…
Our work with permeance and hydraulic permeability tests on the SiN-NP seemed to show that the porosity and pore sizes I had calculated from the STEM images were too high. I used URnano’s TEM to get better quality images and, as suspected, the pore sizes need to be revised smaller. Wafer # 1030 (40 s…
I found another old wafer # 760 and asked Josh Miller to deposit a 25-50-25 OSO stack. He did a standard RTP of 1050 C, 60 s, 100 C/s. (and Josh Miller did the EDP etch, so this is really all his work) I measured a porosity ~4.5 %, and avg. dia. ~40 nm. For…
Ultimately we want to use SiN-NP filters to separate viruses or some other biological species, but repeated attempts to pass 20 nm fluorospheres in water or PBS have failed. Au particles, however, have passed through the filters. This post reports the results of Sarah and I attempting to pass Au particles from 20 to 100…
Following up on our previous work with SiN-NP with varied RIE times, Sarah and I measured permeability and permeance using a new measuring system better suited to the higher permeance and permeability we expect with the larger pores and higher porosity. Using the pressure regulator pictured above, we can set pressures of 3 psi and above…
JP and Josh Miller used the Xactic Si etcher to remove the pnc-Si from SiN-NP samples. I believe they ran cycles until the samples looked visibly like SiN only. Below are some SEM cross-sections showing before and after images of the samples. Sample 1028 with no RIE etch: Sample 1036 with 20 s RIE…
Karl and attempted to pass 10, 20, 40 and 50 nm Au NPs through samples from the center of wafer # 1019 (avg por dia 50-60 nm, porosity ~27%). The bottles of stock Au from BBI solutions do not have the concentrations marked, but according to BBI’s website, they only sell the concentrations provided in…
Karl and I attempted once again to filter particles with the SiN-NP 5 slot SEPCON chips. (wafer # 1019, 27% porosity, avg. pore dia. – 54 nm in the center, 30%, 61 nm at the perimeter, histograms below) We started trying to first pass 20 nm red fluorospheres, then block 100 nm yellow fluorospheres,…
We used 4″ wafers with 40 nm pnc-Si on 50 nm RV SiN (RTP 1050 C, 100 C/s, 60 s). JP ran a series of RIE times from 10 to 50 s with 10 s intervals. (We had initially planned on starting at 70 s based on experiments with 6 ” wafers, but fortunately JP chose…