What ratio should be taken of sulfuric acid and nitric acid for nitration of benzyl chloride?

Hello,

I am trying to etch 2 μm of PECVD SiO2 using a ~4 μm PR mask to create a pattern of 20 * 60 μm. I am using the Oxford ICP-RIE Plasmalab System 100. I have tried multiple recipes, but I have encountered issues such as low selectivity, polymer redeposition, and extremely low etch rates at times. Any suggestions would be greatly appreciated.

Thank you.

Hello,

I am planning to work with acidic piranha solution made from sulphuric acid 98% and hydrogen peroxide 30% (volumetric ratio 3:7).

I worked with this solution before, but this time I want to use it for cleaning of photolithographic masks (soda-lime glass with chrome layer), which is a standard oparation in photomask cleaning.

Standard usage on piranha etch comprise teflon holder to hold/support mask/wafer/sample. But in some applications tweezers could also be desirable (single wafers instead of batches, small volumes of piranha solution).

My question is: which type of tweezers should I choose for this job (what material), especially for operating large surfaces like wafers or lithographic masks? I did not find consistient and comprehensive info about it.

Teflon tweezers seems sturdy and uneasy to use (manipulating glass mask).

Stainless steel could be susceptible for corrosion. Has anyone had experience with it?

Stainless steel coated with PTFE seems viable, but what about scratching PTFE and exposing stainless steel to corrosion?

Maybe some other materials could be used for the job?

I will appreciate any feedback.

Sincerely,

Grzegorz

Hello everyone,

I want to do peak fitting of Ga3d and O2s together in Ga2O3 data using CASAXPS. Now I am confused with line shape, somehow LA and GL both fit but then gives the different concentration of Ga:O. If someone has done it before or has an idea of how to understand this, please let me know.

Thank you in advance.

It has been reported that the motional resistance of QCM is independent of the resonance frequency changes and is directly proportional to the viscoelastic property of the film deposited on the quartz crystal electrode.

As per the Saurbrey equation (applicable only to thin rigid films), resonance frequency change is negatively proportional to mass change.

I want to understand the physical significance as well as the difference between both motional resistance and resonance frequency of QCM and how they are independent of each other.

Thanks in advance!

Hello, My question is related to authentication of ellipsometry for dielectric constant measurement. In my case, I am measuring the refractive index and dielectric constant of Al2O3 thin film on Si substrate. the measured value for refractive index is 1.66 - 1.77 and dielectric constant 2.75 - 3.15. Refractive index values are good match with reported value but dielectric constant value is differ from reported value 7.8. What is the reason of this difference in values? Does it mean ellipsometry is not always good to measure the dielectric constant?

I have a trouble now. I need to use a relatively gentle method to completely remove ODE without damaging the surface ligand(in my case oleic acid coated CuInS₂ quantum dots with only ODE as the solvent). add in Ethanol,acetone or Acetonitrile Centrifuge several times at high speed will damage the surface ligand or alloy shell(ZnS-CuInS₂). So, how should I modify my purification method?

I'm currenting using the Bertsch and bloom method of analysing exchangeable Al in soils. The method says to use nitric acid to buffer the pH filtrates to <3. But Id prefer to avoid using HNO3, would using HCl to acidify the samples be appropriate?

h-index is a tricky basis for comparison between different individuals. In the first instance, some fields do not have large numbers of followers compared to others. Does this mean that the scientists in those less populated fields are not as important as those in the more populated fields? Second, high levels of productivity are often associated with high levels of funding, here again the rich get richer. Third, who is the better scientist, the individual with a small lab who publishes a more modest number of papers with 2 or 3 authors, or the individual with a large group who publishes many papers with 20 or 30 co-authors? I think that the bottom line of all of this is that it isn't really possible to make a fair comparison of individual scientists without understanding their detailed circumstances.

I have used an adsorbent. In FTIR analysis I was found carboxyl, hydroxyl, thiol and amino group in adsorbent. But in EDX result, the elements that can be detected only C, O, Na and S.The N element was not found.

Do you have any idea why this is happening?