Laser Interferometric Temperature Measurement of Heated Substrates Used for High Tc Superconductor Deposition

Abstract

AbstractSubstrate temperature during film growth is an important processing parameter for vapor deposited films of the high Tc superconductors. In this paper we describe a novel, non-contact optical thermometry technique in which the temperature of a transparent substrate or “temperature sensor” is determined from its thermal expansion and refractive index change measured by laser interferometry. The technique is easy to implement and extremely accurate. Temperatures measured with this technique are reported for MgO substrates in varying degrees of thermal contact with a heated backing plate and compared to those measured conventionally by optical pyrometry or thermocouples in close proximity to the sample. The effect of the deposited film on the temperature of radiatively heated substrates will also be discussed.