Market Players, page-90

Just checking the thermal properties of silicon (quartz) is > 1500 oC, which implies that the endurance of WBT chip can be expected to be higher and better.

Now we need a top electrode as a conductor for this cow start. It's interesting that the color of the WBT is similar to copper (hardened bright yellow) which is good as it is almost inert as precious metals like silver. Secret ingredient to add in this tech can be Zircon (for base) which is 4 times cheaper than Silver as well. In summary, WBT could have been a composite of CuO-[[SiO2]x2-Si3N4]]n-Zir-O; man, this structure is golden standard for super hardcore chips.

I get this idea of structure from the MEM-Q Workshop where our CTO is going to. Also, the switching mechanism is solved with various approach as well. FYI, 

http://iopscience.iop.org/article/10.1088/1742-6596/993/1/012028/meta