Blue color indicates roughly 500nm SiO2 thickness. It took about 2.5hours to grow @ 1200c in a pottery kiln style furnace with steam being pumped into it. Picture above on the left shows moisture on cooling wafer. Picture on the right shows unpolished backside of the wafer. Notice the nonuniformity in the growth thickness caused by unequal heating. This is because I don’t have a quartz boat to hold the wafers so I place them face up in the furnace.