In Old Wafers I was discussing how semiconductor fabricating plants that use 150 mm (6 inch) silicon wafers are rather old technology. Over 18 years old. It turns out that that kind of production facility may not yet be obsolete.
A white LED breakthrough at the University of Cambridge could lead to mass production in the UK.This new technology will mean LEDs that cost 1/4 of what they do today. Possibly even less. That would bring LED lights into the cost range of CFLs. Interesting times.
"Its it is a way of making GaN LED die that is a factor of 10 cheaper: growing them on 150mm silicon wafers rather than 50mm sapphire," Professor Colin Humphries told Electronics Weekly.
"The cost of processing a 150mm wafer and a 50mm wafer is the same, or even cheaper in 150mm because a lot of 150mm fabs exist," and raw 150mm silicon wafers are much cheaper to produce than 50mm sapphire wafers.
Everyone would be doing this if it was easy. The critical step is reliably growing GaN/InGaN structures on silicon where the mismatch in lattice constant means wafers bend - preventing lithography - or even break.