Understanding netlist IF statements

Question

I`m reviewing this paper on how to do SPICE modelling for an FG transistor: https://digital-library.theiet.org/content/journals/10.1049/el.2011.0458

Inside there is a figure provided:

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I`m completely at a loss at to what this netlist/IF statement at the bottom of the figure says here. What is it saying? What is Gtun and Ginj?

• periblepsis: What do you need to understand? It's just a B current source device. The tun and inj are just names given to two different ones. And the next two words on each are the terminal connections. The value part is just a formula, which can be conditional using an if statement. Perhaps you are completely unfamiliar with the fact that Spice uses cards and was originally developed before graphics! Back in the day when there were no graphics terminals at all. So it just takes text cards -- the old punch cards. The G is just one of those punch cards. Spice still uses them.
• periblepsis: Every time you screw around with a schematic, Spice ignores all that crap and creates a card deck. You can look at it by finding some menu option that will give you the Spice netlist. That is what it REALLY uses. Not the schematic. That's just a pretty picture for you. Not for the simulator, which doesn't really care about it. Most Spice programs allow you to place these cards directly into the schematic, if you want. In fact, you could use ONLY these cards and be just fine. No schematic drawing at all! The schematic editor is really just a Spice card generator.
• periblepsis: Stop using the schematic editor for a while. Get used to just plopping down cards like we used to have to do back in the day. You'll never have a question like this, again. ;)
• starboy: Thank you. So what is Tun_expr and Inj_expr? From what I understand, say for the first line - is it saying that for nodes 'vfg1' to node '0' the value is 0 IF (V(Vtun)-V(Vfg)) > Vdd) condition is met? Tun expr being the name of the current source? Very new to this but keen to learn it better.
• periblepsis: tun_expr will be found somewhere on the schematic. It's possible that it is also discussed in the referenced paper. Just ask for the netlist and post it here. But if it is a schematic only in the paper, then you may need to write the authors for their netlist. It has to be there. But read the paper carefully first. Then write them if it's not clear from the paper itself. It's possible that you are supposed to figure it out for your specific situation.

Answer 1

From a Wikipedia article Floating-gate MOSFET

The floating-gate MOSFET (FGMOS) ... is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) where the gate is electrically isolated, creating a floating node in direct current, and a number of secondary gates or inputs are deposited above the floating gate (FG) and are electrically isolated from it.

...

The first report of a FGMOS was later made by Dawon Kahng and Simon Min Sze at Bell Labs, and dates from 1967.

The Wiki article does not show the structure of multiple-input FGMOS devices. Your reference may have a representative picture of the kind; if not, you can easily find it elsewhere, as FGMOS is a well established (since 1967) device type. For example, here is one from a researchgate paper

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Back to the Wiki article and your question. Of the two voltage-controlled current sources of your question, Gtun is used to model a Fowler-Nordheim tunneling mechanism; Ginj, models a hot-carrier injection mechanism. See also the section Small signal of the Wiki article.

If your reference does not specify the expressions Tun_Expr and Inj_Expr used in the netlist's IF statements, you can find those elsewhere. Fowler-Nordheim tunneling and hot-carrier injection are well studied mechanisms, extensively discussed in textbooks and articles, including formulas proposed for SPICE models. Also, the information used to model these phenomena can be found while browsing course notes of engineering schools.