Thermal Analysis and Control for Sputtering Deposition of High-Tc Superconducting Films

Abstract

For the preparation of high-quality films of high-Tc superconductors (HTSC) on crystalline substrates, it is necessary to control the substrate temperature accurately during deposition. This study shows that thermal radiation heat transfer in the deposition chamber governs the substrate temperature. The application of thin-film optics yields the emittance of the substrate holder-substrate-film composite as a function of the thickness of the growing film. In a single-target off-axis sputtering system, the substrate temperature is measured during film deposition using a novel method for the attachment of a thermocouple to the substrate front surface. For constant heater power, the measurements show a decrease of the substrate temperature, in agreement with the theoretical prediction. Based on the substrate emittance variation determined in this work, a pyrometric in-situ temperature measurement technique can be developed.