New design of a microcalorimeter with enhanced accuracy through the consideration of thermal loss of the membrane platform

We report on the development of a Si-N/Si based microcalorimeter for measuring specific heat of small samples in a wide temperature range. By using well-known MEMS fabrication techniques [1], the heater and sensor elements are integrated on the Si-N membrane. The fabricated calorimeter is operated by a custom-made program based on the curve fitting method [2]. By comparing measured thermal conductance ($\lambda )$ from the membrane platform to the thermal reservoir in three different designs, we find $\lambda $ can critically affect the accuracy of measurement, and that the geometry of metal lines is a key parameter to control$\lambda $. Based on those findings, we provide a new design of microcalorimeter resulting in the specific heat of Cu ($\sim $ 300 $\mu g)$ consistent with literature values within 5{\%} in a temperature range between 20 and 300 K. \newline {\dag}parkyd@phya.snu.ac.kr, khkim@phya.snu.ac.kr \newline [1] D. W. Denlinger \textit{et al.}, Rev. Sci. Instrum. 65, 946 (1994); S. L. Lai \textit{et al.}, Appl. Phys. Lett. 67, 1229 (1995). \newline [2] K. S. Suh \textit{et al.}, J. Korean Phys. Soc. 49, 1370 (2006); J. S. Hwang \textit{et al.}, Rev. Sci. Instrum. 68, 94 (1997).