Preparation of thermoelectric Si:B/SiGe multilayer structures on quartz glasses by RF-magnetron sputtering with layer-by-layer annealing methods

We prepared boron-doped Si/Si0.8Ge0.2 (Si:B/SiGe) multilayers sputter-deposited on quartz glass substrates, and investigated their structural and thermoelectric properties. These samples were processed by using conventional whole-layer annealing and layer-by-layer annealing methods. Si:B/SiGe multilayer samples annealed layer-by-layer showed good periodicity with well-defined interfaces as compared with conventionally annealed samples (whole-layer annealing). However, Ge diffusion was observed at the interfaces near substrates since the SiGe layer near the substrates suffered a longer integrated annealing time during the layer-by-layer annealing process. It was found that the Si:B/SiGe multilayer annealed layer-by-layer showed thermally stable thermoelectric properties in a wide temperature range from 50 to 800 °C. The present experiment proved that the layer-by-layer-annealing method is an effective way of achieving stable and reliable thermoelectric properties in Si:B/SiGe multilayer micro-thermoelectric devices.