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Cog·i·ta·tion [koj-i-tey'-shun] – noun: Concerted thought or
reflection; meditation; contemplation.
Kirt [kert] – proper noun: RF Cafe webmaster.
Scientists at Sumitomo Electric
Industries has figured out how to grow gallium nitride (GaN) crystals
on inexpensive GaN substrates rather than on sapphire or silicon carbide
substrates. Lattice dislocations (imperfect matching between GaN and
the sapphire or SiC) cause inefficiencies in the operation of the blue
laser diode applications that GaN is predominantly used for. GaN crystals
grown on GaN substrates are nearly perfect. Still, GaN is expensive
at around $10k for a 2" wafer compared to around $200 for a Si wafer
4-6 times as large. Roughly 1000 diodes can be produced from a 2" wafer,
making the die cost alone about $10. Blue lasers can yield a storage
capacity of 27 GB on a standard DVD (a 6x increase). Don't expect to
find one of these babies in the next Sunday sale flyer PC system because
the first production DVD drives are now selling for about $3800 from