{TAIL ~ A thickness} of about 700 to 900 Å of a silicon nitride film is suitable for {HEAD ~ a refractive index} of about 1.9 to 2.0 
{ TAIL ~ A thickness } of about 700 to 900 Å of a silicon nitride film is suitable for { HEAD ~ a refractive index } of about 1.9 to 2.0
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH