I'm currently doing a set of simulations on penetration depth of ions in electronic devices, and I'm wondering whether or not the crystal structure of the materials in the backend (dielectrics, metallization) in a typical Silicon process has an effect on stopping power of these compounds. The most impact I'd expect for Silicon dioxide, which in the case of PVD and/or CVD deposition tends to be pretty amorphous, while a thermal oxide seems to be much closer to a crystalline form. Now the question is how much of a difference should I expect? My gut feeling is that for a deposited amorphous oxide layer, the density should be somewhat less than that of a perfect crystal. But is the difference large enough to actually make a difference in stopping power of the oxide?
I'm aware that stopping of ions in itself is somewhat of a stochastic process such that the resulting range of the ions is subject to a statistical distribution already on its own, therefore I wonder if it actually would make a noticeable change if the density of the oxide layer would lower by a few percent...
Yes, generally there is a clear difference in density beween amorphous and SiO2 crystalline phases. Amorphous SiO2 (2.2 g/cm3), cristobalite cubic phase (2.33) and trydimite hexagonal (2.28) are realtively close in densities but have lower density than alpha rhombohedral hydrothermal quartz phases (2.65 g/cm3).
In your case I believe the substrate is glassy silica, the CVD and PVD methods are supporting very similar densitites of deposited structures.
Thanks for the clarification. This confirms what I deduced myself: The density of amorphous SiO2 as deposited using CVD and PVD methods is slightly smaller than the 2.32 g/cm³ usually given for Quartz in literature, but still close enough such that the effect is small and can be assumed an second-order effect.
Dear Florian E. Teply
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the amorphous materials always characterized by defects or dangling bonds so it has a random structure and poor order also it may has many pores. The crystalline one is vise-versa and also the amorphous materials may have dimensions higher than the crystalline one. Due to the aforesaid the amorphous materials have density lesser than the crystalline one. wishing this may be useful.
Dear Dr. Florian E. Teply
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Yes, there is a little difference in density between amorphous and crystalline phases of the same materials, Usually the density of crystalline is larger material amorphous. This is due to the structural defects and porosity nature which characterizes the non crystalline materials. I already measured the density of both and I found a difference.Please for more details you can reference of my RG page
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