How oxygen vacancies store data

33:45>> knowing knowing what we use it for now. >> Yeah. Yeah. I mean, it's insane. Okay. So, let's let's talk about this veilance charge mechanism that I was telling you about about how the memberister works. Here's the idea. Um, so I told you, right? He he got a titan titanium electrode, a platinum electrode, and in the middle were oxygen vacancies. Now, vacancies is something that I alluded to earlier when I was talking about the holes. The holes are vacancies in the sense that I have taken something out. But now those those holes where I took that thing out, those are mobile just like the the the stuff that I took out. Those are mobile elements. And if those mobile elements can rearrange, they can create

34:26electronic components on their own, right? In the same way that a ptype >> semiconductor can use the holes to do all of its electronics. The point being that vacancy is not uh stationary. It has the ability independent of the thing that left to move on its own. >> Yeah. Exactly. >> Okay. So, um let's get into a little bit more about how these oxygen vacancies work because this is going to be the central thing we need to understand about why the physics of this modern paper is working. Okay. Um when you have these two electrodes, you've got a positive electrode and a negative electrode, right? You you what you do is

35:08a switching process. Okay? So this is effectively how it works. Let's say I've got a top electrode and a bottom electrode. In this case, it's like silver and um titanium on on the bottom. But it doesn't really matter what the identity of the two electrodes are yet. It's going to matter later. What happens is in order to understand what this veilance charge mechanism is let's let's try to think of a analogy a simple analogy okay imagine like a really thick densely packed forest like the forests of Endor in the Star Wars episode 6 return of the Jedi. >> Okay. >> Okay. >> Okay. >> Now if you remember the forest of Endor

35:51that they had those like motorbike thingies. Um I actually looked up what they were called. that were called forest motorbikes. 74Z speeder bikes. Okay, remember like they they they like zoom through the forest at really really high speed. Now imagine a really really dense forest. Okay, if you've got a speeder bike in a really really dense forest, you're going to crash. >> Yeah. You have to be an uh Lewis Hamilton. >> Yes. Yes. And even then, you know, like like I'm talking about like there's there's a tree literally everywhere. It's it's it's not it's not feasible. >> It's not going to work. It's not going to work. So, what you could do instead is have a bulldozer come in or let's say

36:32a really high wind and that's going to take down some of the trees. [snorts] >> Yeah. Okay. When you take down some of the trees, that's kind of like creating oxygen vacancies in something like a transition metal oxide like hnneium oxide or titanium dioxide, right? These are transition metal oxides that are metals bonded to oxygen. that's in the middle sandwiched in between the two electrodes. Right? If I've got an electric field, the oxygen which has these like it's it's just got these properties where it wants to go towards the negative electrode. Right? Um this is why oxygen is so reactive and why it rusts everything. Um the oxygen is going to start moving. When it starts moving,

37:13it's going to leave behind holes. >> Okay? So, it's kind of like the trees are coming down and now I've got a pathway. Now, my motorbike can move really fast. The motorbike in this analogy represents the electron. >> The electron is piggybacking on these vacancies. >> And and it it's and part of your point is being until the wind or the bulldozer comes and knocks the trees over, which is the oxygen leaving. >> Um [clears throat] the electrons can't move through. >> Yeah. So that would be a high resistance state, right? That's one of the states that we were thinking a memor should have. It's got a memory, right? There was no wind and so I am at a high resistance. Now all of a sudden I

37:54applied an electric field. I got a low resistance. Can I go backwards? Yeah. Just apply the electric field in the other direction. The trees stand up. Low resistance. >> Got it. Got it. >> Right. This is the mechanism behind the switching behavior. The set and the reset that we think of in memoristers. That's the memorister jargon. It's like you set it to the low resistance state. So then there's like conduction happening. So that's your one let's say. And then you reset it back to the high resistance state. So then the the trees are all up, the vacancies are back, the oxygen is back. I mean, there's no more vacancies, and the electrons don't have a highway to go through. >> And what's interesting about this is you can go, you have the ability to return

38:35to to return back and forth in between each of these states. >> Exactly. So now you've got a cycling, >> right? >> And that's something that you need for nonvolatile memory, right? >> Okay. That's effectively what this um vacancy mechanism is. >> Mhm. >> Got it. Now, a lot of times now we're going to try and use half oxide. The advantage here is that halfneium oxide is something that silicon chip makers have already been using in transistor gate stacks. It will it's already replaced um the silicon dioxide