Bias series continued
This is a continuation of the silicon substrate bias series. I have added several more data points to highlight the trend. Below are the TEM micrographs, pore distributions, average diameter/porosity/density plots. It would appear that the “optimal” bias is at 05W if we are using porosity as a metric.
I also performed a short temperature series on a 15 nm film deposited with 05 W substrate bias. The red dots are the 05 W condition and the blue x’s are the standard 25 W condition. For low temperatures the two membranes are very similar. However, between 850 and 950 C there is a considerable increase in size and density of the pores in the 05W sample.
Very nice and convincing. All your samples were identical except for the bias, right? I wonder if the optimum might be a function of the thickness of the silicon film- we know it’s more difficult to produce pores for thinner films and vice versa. So, could the optimum depend on thickness and if so, what would the “best” results conditions be, if we want to optimize, pore density or pore size, or any other parameter? I am still thinking about getting a huge number of small pores…