Thermoelectric infrared microsensors based on a periodically suspended thermopile integrating nanostructured Ge/SiGe quantum dots superlattice

Katir Ziouche (1) , G. Savelli (2) , Zahia Bougrioua (1) , D. Hauser (2) , P. Lejeune , P.M. Michon (2) , Tuami Lasri (1) , Didier Leclercq (1)

1 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520
2 CEA, LITEN - Thermoelectricity Laboratory

This paper presents an original integration of polycrystalline SiGe-based quantum dots superlattices (QDSL) into Thermoelectric (TE) planar infrared microsensors (μSIR) fabricated using a CMOS technology. The nanostructuration in QDSL results into a considerably reduced thermal conductivity by a factor up to 10 compared to the one of standard polysilicon layers that are usually used for IR sensor applications. A presentation of several TE layers, QDSL and polysilicon, is given before to describe the fabrication of the thermopile-based sensors. The theoretical values of the sensitivity to irradiance of μSIR can be predicted thanks to an analytical model. These findings are used to interpret the experimental measurements versus the nature of the TE layer exploited in the devices. The use of nanostructured QDSL as the main material in μSIR thermopile has brought a sensitivity improvement of about 28% consistent with theoretical predictions. The impact of QDSL low thermal conductivity is damped by the contribution of the thermal conductivity of all the other sub-layers that build up the device.

Domaines: Sciences de l'ingénieur [physics]

Katir Ziouche, G. Savelli, Zahia Bougrioua, D. Hauser, P. Lejeune, et al.. Thermoelectric infrared microsensors based on a periodically suspended thermopile integrating nanostructured Ge/SiGe quantum dots superlattice. Journal of Applied Physics, 2014, 116 (4), 043701, 7 p. ⟨10.1063/1.4891020⟩. ⟨hal-01055042⟩