In this post, pores from four different structures are compared. Those four different structures are nitride/silicon/nitride (NSN), nitride/silicon/oxide (NSO) , oxide/silicon/nitride (OSN) and oxide/silicon/oxide (OSO) . The thicknesses of nitride, oxide and silicon are 30nm, 30nm and 25nm, respectively. Wafers with four different structures were etched first to remove the substrate. The four different free…
In my previous post of Morphology evolution in pnc-Si membrane (2), see https://trace-bmps.org/datablog/?p=14769&preview=true , I showed that membranes (30SiN-25Si-30SiN) annealed at 700C show us an intermediate morphology in the pnc-Si membrane. I did some further investigation in the past week on this intermediate morphology. Compared with the previous test which membrane was annealed at 700C…
In the last post, we have discussed the intermediate state of the membranes which shows the irregular shape pores and silicon nanocrystals after annealed at 700C. Last week I did a quick test on the same nitride membrane with a different annealing process to verify this intermediate state. I run two different heat treatments. The…
In this post, I would like to sum up all different annealing scenarios, which corresponding to different morphologies of the pnc-Si membrane so far we have observed. It should be very helpful to understand the evolution of the pore formation during the annealing. This whole evolution I believe, not only applies to the oxide/silicon/oxide stack,…
Now we already confirmed that pores are able to form in both oxide/silicon/oxide and nitride/silicon/nitride system. Here comes an interesting question- how about nitride/silicon/oxide and oxide/silicon/nitride system? In the past week, another two different stacks including SiN(30nm)/ a-Si(25nm)/SiO2(30nm) and SiO2(30nm)/a-Si(25nm)/SiN(30nm) were tested. The nitride film was deposited with 25 W bias and the silicon with…
Last week, I deposited silicon nitride/ amorphous silicon/ silicon nitride stack and then annealed the free standing stack after etching the substrate. The nitride film was deposited with 25W bias and the silicon film with 5W bias. The thickness for the nitride film is 30nm where it is 25nm for silicon. One of the initial…
A few weeks ago, professor Mike Aziz in Harvard University helped to annealed two samples and in-situ imaged the early stage of pore formation using their Jeol2010-hot-stage-TEM. The oxide seemed intact during the process. The sample was unannealed 20(bottom)/15(a-si)/10(top) three stack with removing the substrate. The first sample was heating to 693C. They took one…
The thickness of bottom oxide in the ‘sandwich structure’ is also a key factor to affect the pore morphology. In last few weeks I deposited five wafers with different bottom oxide thicknesses and they were 05/15/20, 10/15/20, 20/15/20, 40/15/20 and 100/15/20. Then I annealed them at 1000C for 1 minute with a 100C/s ramp rate….
Last few weeks, I deposited a couples of wafers to test the effect of oxide thickness on pores. In addition to previous data, I deposited another two wafers, one with 1nm top oxide and the other with 100nm top oxide. I summed up all data from the top oxide experiments. The first image is the…
Last week, I did another two wafers with different top oxide thicknesses to verify my hypothesis about the top oxide thickness effect on pores. The wafers were 20/15/03(bottom/middle/top) and 20/15/40. According to the hypothesis, the porosity of 20/15/03 would continue decreasing, where for the 20/15/40 structure, the porosity might drop. Same tip I used before,…