first thermocouple temperature measurement because typical oxidations last for multiple hours siphons slowly feed water into the bubbler flask 36 and into the heating bath 40 in order to maintain water levels sufficient for oxidation typical al x ga 1 x as x gt 0 8 oxidation temperatures range from 400 435 u00b0 c and are measured by the thermocouple 40 inside the furnace 34 the flowmeter 48 controls the amount of nitrogen that enters the flask 38 and a thermometer 54 is used to measure the temperature of the bath 56 for those skilled in the art the simple single zone tube furnace and the associated bubbler and siphons can be replaced by the more commonly used multiple zone tube furnace with a pryogenic torch subsystem that is used in the thermal oxidation of silicon in the commercial manufacturing of silicon integrated circuits the torch subsystem bums high purity h 2 with high purity o 2 to form steam with the minimum amount of impurities since h 2 and o 2 are used the bubbler and siphons are not necessary a number of dielectric stack structures have been studied with the goal of creating large area stable buried oxide structures such as sbrs with broadband high index contrast mirrors in the simplest design a structure with alternating layers of gaas and alas is grown and 500 u03bcm circular mesas are defined and oxidized in an attempt to form gaas al x o y dielectric mirror stacks upon oxidation however this type of structure can suffer from severe deformation for.