CNx/Si Thin Heterostructures for Miniaturized Temperature Sensors

CNx /Si thin heterostructures were synthesized on Si ^111& substrates by XeCl* excimer laser ~l5308 nm, t FWHM>30 ns) ablation of nuclear grade graphite targets in 5 Pa nitrogen at room temperature. We investigated the current–voltage and capacitance–voltage characteristics of heterostructures obtained at 77 and 300 K. We monitored their conductance and capacitance as a function of the bias voltage applied, in the 100 Hz–1 MHz frequency range. Our results revealed the formation of deep localized electron states both inside the thin CNx films and at the CNx /Si substrate interface. The investigations evidenced that conduction through the CNx /Si thin heterostructure is of trap-assisted tunneling type. The experimental studies show quite a large decrease in capacitance and increase in conductance with the increase of applied frequency. The capacitance of the CNx /Si thin heterostructures increases with a decrease of the temperature. All the results support the potential development of new types of high sensitivity temperature sensors.