Specific heat measurement of thin suspended SiN membrane from 8 K to 300 K using the 3ω-Völklein method

Hossein Ftouni (1) , Dimitri Tainoff (1) , Jacques Richard (1) , Kunal Lulla (2) , Jean Guidi (3) , Eddy Collin (2) , Olivier Bourgeois (1)

1 NEEL - TPS - Thermodynamique et biophysique des petits systèmes
2 NEEL - UBT - Ultra-basses températures
3 NEEL - InfoLab - Informatique & Réseaux

We present a specific heat measurement technique adapted to thin or very thin suspended membrane from low temperature (8 K) to 300 K. The presented device allows the measurement of the heat capacity of 70 ng silicon nitride membrane (50 or 100 nm thick), corresponding to a heat capacity of 1.4x10−10 J/K at 8 K and 5.1x10−8 J/K at 300 K. Measurements are performed using the 3ω method coupled to the Völklein geometry. This configuration allows the measurement of both specific heat and thermal conductivity within the same experiment. A transducer (heater/thermometer) is used to create an oscillation of the heat flux on the membrane; the voltage oscillation appearing at the third harmonic which contains the thermal information is measured using a Wheatstone bridge set-up. The heat capacity measurement is performed by measuring the variation of the 3ω voltage over a wide frequency range and by fitting the experimental data using a thermal model adapted to the heat transfer across the membrane. The experimental data are compared to a regular Debye model; the specific heat exhibits features commonly seen for glasses at low temperature.

Mots clés: specific heat; thermal conductivity; thin film

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Hossein Ftouni, Dimitri Tainoff, Jacques Richard, Kunal Lulla, Jean Guidi, et al.. Specific heat measurement of thin suspended SiN membrane from 8 K to 300 K using the 3ω-Völklein method. Review of Scientific Instruments, 2013, 84 (9), pp.094902. ⟨10.1063/1.4821501⟩. ⟨hal-00919345⟩