Cryogenic Microwave Performance of Silicon Nitride and Amorphous Silicon Deposited Using Low-Temperature ICPCVD

Fabrication of dielectrics at low temperature is required for temperature-sensitive detectors. For superconducting detectors, such as transition edge sensors and kinetic inductance detectors, AlMn is widely studied due to its variable superconducting transition temperature at different baking temperatures. Experimentally only the highest baking temperature determines AlMn transition temperature, so we need to control the wafer temperature during the whole process. In general, the highest process temperature happens during dielectric fabrication. Here, we present the cryogenic microwave performance of \(\hbox {Si}_{3}\hbox {N}_{4}\), \(\hbox {SiN}_{x}\) and \(\alpha\)-Si using ICPCVD at low temperature of 75 \(^{\circ }\)C. The dielectric constant, internal quality factor and TLS properties are studied using Al parallel plate resonators.