Germanium, like Silicon, is a semiconductor material.
Germanium was actually more common than Silicon in the early days of semiconductor manufacturing, but it turned out Silicon had a higher tolerance for heat AND was less expensive to make wafers for (silicon is literally dirt-cheap - a large proportion of "dirt" is Silicon, along with Aluminum and Iron).
... the relatively poor heat capacity is going to cause it's OWN issues.
BitFury reports to use immersion cooling
on their website to nearly double their efficiency. This would probably give them an advantage to understand the tech well if the next generation is going to run hotter. Seeing those numbers makes me think about researching into it more.
Even when 7nm reaches actual production - what are the YIELDS going to be like?
They are reporting
10 Th/s with 500W on the GMO 7nm chipset, so that's about double the efficiency of an S9 - not a large jump like 28 to 16/14nm - but still significant.
You're addressing a question there.
Yield has to do with how many usable die you get from a wafer as a percentage of the POSSIBLE die you should get if there are no flaws.
Efficiency - I'm starting to question their figures a LOT, 28nm to 14/16nm in Mining ASIC so far has seen about half the power usage per hash in most usage on comparably optimised products (S7 to S9 for example).
Given that quantum effects have been limiting the gains in both possible clock rate AND in efficiency at an increasingly worse level per generation for GENERATIONS now, I doubt we're going to see an improvement of 2.5 TIMES the efficiency from 7nm - even if it really IS 7nm and not just CALLED that while having real feature size closer to 9-10 nm range.
