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第1楼2015/12/20
Answer 1: From your description, I guess your instrument is Thermo 250 or 250xi. First of all, the sputtering rate on surface analysis instrument is serving as a "reference" only meaning its never the REAL etch-rate on YOUR SAMPLE. However, its still serving as a very important reference for knowing some thickness information because otherwise you have no idea at all how the thickness relationship to be on your sample. The value you see in your software should be calibrated by the service-engineer and as you said by using Ta2O5 as standard. Ta2O5 (or some use SiO2) are typical samples using for sputtering rate check on surface analysis instruments.
And further to your question because sputtering rate is on Ta2O5 and you do not know what is actual rate on YOUR SAMPLE. In this case, what exactly is your sample material? Sometimes it may be possible to get some reference on the internet about different materials sputtering rate as reference to SiO2 or Ta2O5. So give it a search on Google or Baidu for it. On the other hand, certainly it is impossible to know sputtering rate on ALL materials in the world. So in this case, a very typical way when explaining a depth profile data, one would put into the data stating "sputtering rate is xx nm/min on Ta2O5/SiO2 standard sample". It is widely accepted by the surface analysis field.
Answer 2: Usually no need to consider the angles how photo-e comes out because basically they're coming out at ALL angles. Usually what would affect your data are:
(1) Angle between X-ray and Analyzer
(2) Angle between Analyzer and your sample-flat-surface.
For (1) it is instrumentation so you don't care much.
For (2), it may relate to later part of your question. As continue to guess your system is Thermo 250 or 250xi, YES the analyzer is perpendicular to the sample. Its called as Take-of-angle (TOA) 90-degree. At this angle, the sensitivity would be highest (just imagine because sample is directly facing to analyzer) while the detection depth is deeper. If one tilt the sample stage so making the TOA is smaller like 90 > 45 > 30..., then sensitivity will get lower but detection depth is more shallow. This is what being called Angle-Resolved XPS.
hankouminjing
第2楼2015/12/21
摆度
第5楼2015/12/29
The reason for the doublet peak is due to spin orbital splitting (or called spin orbital coupling). Please see above page for explanation. When spin happen in favorable direction, the binding energy becomes lower (e.g. 2p3/2 peak) while the opposite case binding energy become higher (e.g. 2p1/2 peak). This phenomena will always happen but in some cases the energy difference is so small and as in XPS analysis it may or may not able to separate the 2 peaks.
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第7楼2015/12/31
They are not the same electron. In XPS, X-ray keep shining onto the samples and excites the photo electrons out.
Still taking the example of p orbit:
- l = 1
- so J can be 1/2 or 3/2
- For J = 1/2, it can be only 1 state = 1/2 (2 electrons)
- For J = 3/2, it can be 1/2 or 3/2 (4 electrons)
- So this is why commonly we say 2p3/2 and 2p1/2 ration are 4:2 = 2:1 (area of the XPS peaks)
***Continue the concept for d or f orbit to get to the 3:2 and 4:3 area ratio.
So we know a probability of 2:1 hitting ratio (if only considering 2p) between the 3/2 and 1/2 splitting peaks. In some sense, you are right to say that "at just 1 moment" when "1 photo electron" is generated, then it has to be EITHER 2p3 OR 2p1. But the thing is X-ray keep shining and photo e- keeps generating and it will get probability of getting both so in a real XPS spectrum you see 2p3 AND 2p1 at the same time.
I hope it can make some sense now.