How much does it costs to manufacture? Are there any other benefits from using isotopically pure Si-28? Are there any other isotopes used in common thermal conductive material that are more conductive?
The point of improving the thermal conductivity of silicon is that silicon is what chips are made of instead of, say, diamond.
Of course cost would have to be acceptable.
I was thinking more about isotopes of copper than carbon but I can't find data about thermal conductivity of isotopically enriched copper.
I don't think there would be much difference because much of the conductivity of copper is from the conduction electrons, not phonons. Isotopic purification increases thermal conductivity in silicon because it decreases phonon scattering.
Isotopically pure diamond, now there's something to look at.
https://en.wikipedia.org/wiki/Isotopically_pure_diamond
"The 12C isotopically pure, (or in practice 15-fold enrichment of isotopic number, 12 over 13 for carbon) diamond gives a 50% higher thermal conductivity than the already high value of 900-2000 W/(m·K) for a normal diamond, which contains the natural isotopic mixture of 98.9% 12C and 1.1% 13C. This is useful for heat sinks for the semiconductor industry."
I understand isotopically pure Si-28 may be preferred for quantum computing devices. The Si-28 has no spin or magnetic moment, reducing the rate of decoherence of certain implementations of qubits.
https://spectrum.ieee.org/silicon-quantum-computing-purified...