Second try at USSR integrated circuit analysis

In the previous post, I logicked my way into the geometry of a transistor. But in fact, the geometry turned out to be wrong since none of the circuitry made any sense. So I decided to start from this diagram, which is similar to the 74141 diagram. Which makes sense since the К155ИД1 is the same as the 74141.

 From  chipinfo.ru .
 From the 74141 datasheet.

From the 74141 datasheet.

So if I look at the A input, I should see an inverter and a second inverter. The outputs from these go to output transistors.

Next, I drew one of the transistors in the above circuits as a generic three-terminal device: 0 for a terminal with no region around it, 1 for one region, and 2 for two regions.

Then, I drew the inverter circuits based on what I saw on the chip.

Then I logicked my way to a reasonable schematic. The two-terminal question-marked component seems to be maybe a resistor. 0 seems to be the base, 1 is the emitter, and 2 is the collector.

OK, this makes some sense. The two transistors on the left are an inverter. X taps off the output of the inverter, and the third transistor on the right is what you'd typically see in a 7400-series input. It's just two diodes back to back in a current-steering circuit. Since it taps off the emitter of the output, it is the inverse of X.

That means that we have this interpretation of a transistor:

Now, let's take a look at the outputs.

OK, that's not right according to the datasheet. But on the other hand, it could work. If A is high, and if DCB = 100, then we want 9 to sink current and 8 to be off. If A is high then X is low, which means that as long as the base is active, 9 will sink current.

I still haven't identified the protective zener diodes on the outputs.

So if the terminal designations are correct, then it's possible that this is the doping schema.

IMG_20170618_121522.jpg

So what I've been calling the "hillock" in the middle of the rectangular region is perhaps the p-doped base. Again, this is weird compared to what you usually see, which is the collector completely surrounding the base.

The collector probably has an n+ region, which improves connectivity. It is embedded in an n or n- region forming the collector.

Note that I think the base contact seems to overlap into the rectangular region. If the rectangular region is n-doped and somehow connects to the collector, which is perhaps an n- region, then this may form a Schottky diode, meaning that these transistors are Schottky transistors.

So technically the collector does surround the base, it's just that it does it through a differently doped region.

Again, I don't have enough knowledge of IC fabrication to know whether this would work. But it seems... logicky?