On temperature coefficient of resistance of boron-doped SiGe films deposited by sputtering

Silicon–germanium films, doped with boron, were deposited on oxidised silicon substrates by RF magnetron sputtering. The post-deposition dopant activation and film crystallisation was done by annealing in the temperature range from 580 to 900 °C. The structural changes in the silicon–germanium films caused by the presence of boron and annealing were investigated by high-resolution transmission electron microscopy. The temperature coefficient of resistance (TCR) was characterised in the temperature range from room temperature to 210 °C and correlated to the nano-structure of the films. The TCR values were explained by the contribution of different scattering mechanisms and confirmed by low-frequency noise measurement. Very low values of TCR can be obtained by selecting appropriate boron content and post-deposition annealing conditions.