I was thinking about this some time ago and came to the conclusion that it is utterly impossible to talk about creating sentient AI with the binary computer technology that we are using today. In order for us to create sAI, our entire technology would have to completely change to something else, likely along the line of analog to work as a single system instead of constant switch between 1 and 0. And that is likely centuries away, as I do not see humanity doing a complete technological rehaul of the entire hardware stack we're deploying today.

As for what consciousness actually is, I think the closest description is the summary of oneself. Meaning, all the computational power of the brain as a whole forms a person - a computational powerhouse with its own identity. That goes then to discussions where the "I", as in ego or oneself, ends. Is it at the limb, like a hand, or is it at an indivodual fallen hair or a dead skin flake? How about sperm or egg, is it still me?

Then we have the conundrum of people who get brain damage or some kind of degenerative brain desease, like Alzheimer. Where you can clearly see "them" fading away and you observe just a shell of a human being. So where is this "I" then? What defines it?

All of these are quite esoteric conversations more suitable for occasions where a lot of alcohol and few good friends are involved :)