A long time ago, Charles did Asymmetrical Oxide Experiment to test how the asymmetrical oxide affects the pores, see Asymmetrical Oxide Experiment. He deposited three structures, which were 40/15/40, 40/15/20 and 20/15/20. It showed that when the thickness of top oxide decreased from 40nm to 20nm while kept the bottom oxide at 40nm, the porosity…
Recently I did some further research on the agglomeration in SiO2+Si layers. On my first post about agglomeration,I found that after annealing at 1000ºC for 1 min without susceptor, 15nm thick Si layer agglomerated and the average diameter of agglomeration islands is around 200nm. This time, I deposited three different thickness of top Si layers…
It seems that pores are only formed in the “sandwich structure” on certain process. So in order to verify this conclusion, I annealed two layers structure (20nm sio2+15nm si) to test the agglomeration theory. The other parameters in depositing and annealing are same to typical sandwich structure process (1000°C anneal, ramp rate 100c/s, w/o bias,…
In order to figure out the relationship between grain size and pore size, I tried to use XRD measurement to determine the grain size by Scherrer equation. t = kλ/(B cosθ) where t is the average grain size, k is the shape factor that is in the range 0.87-1.0 (it is usually assumed to be…