I'm thinking it's light sensitive receptors, but then it could possibly be either pixels or film as well. I'm not really sure. So, if anyone is completely certain of what is etched into the surface of a digital camera sensor, please let me know.

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    Could you explain what you think the difference between a "light sensitive receptor" and a "pixel" is? – Philip Kendall Oct 29 '18 at 17:20
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    I'm voting to close this question as off-topic because it about how silicon wafers are etched to make imaging sensors. It does not include any concern with how that affects the way such an imaging sensor might be used to actually create a photograph, nor does it indicate concern about how one might use such a sensor differently, based on an answer to this question, for the purpose of creating photographs for artistic, historical, or documentary purposes would. – Michael C Oct 29 '18 at 17:51

At the most basic level, digital camera sensors are arrays of photodiodes, semiconductor devices that generate electric current when exposed to light. The means by which photodiodes create electron-hole pairs when exposed to sufficiently energetic photons is called the photoelectric effect, described by Albert Einstein in a 1905 paper, and for which he won the 1921 Nobel Prize ("for his discovery of the law of the photoelectric effect").

There are different types of digital camera sensors (CCD, CMOS, etc.), but at a fundamental level, their light collection cells — pixels, "sensels" (sensor pixel), photosite, whatever you want to call them — operate on the photoelectric effect.

Regarding how the photoelectric effect works, or how semiconductors are etched onto silicon, that's beyond the scope of Photo.SE. I suggest some of the following questions (amongst others) at sister Stack Exchange sites:

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  • How are such photodiodes formed by etching the surface of a silicon wafer? – Michael C Oct 29 '18 at 17:46
  • @MichaelClark understood. A few links to *.SE are possibly in order. – scottbb Oct 29 '18 at 17:54
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    At the "how are the arrays etched to a substrate" level this question is sort of off-topic for Photography.SE. The answer is "using various methods for semiconductor etching, possibly specific to photodiode arrays". – user31502 Oct 29 '18 at 17:55
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    @jdv Yes. Really, the question is probably OT, but a succinct introductory-level answer, pointing to on-network resources, is not a bad thing, IMO. – scottbb Oct 29 '18 at 17:57
  • @scottbb agreed, and I'm not lobbying for this Q&A to be removed. (Though, it is right on the edge of OT if you were to press me for a decision.) Just further discussion along the lines of the comment to this answer is... not great for Photo.SE. This answer captures the question "what is etched onto the substrate" with as much detail as I think it needs, and the refs to research on one of the other SEs is also good. – user31502 Oct 29 '18 at 18:02

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