Investigation of a Microcalorimeter for Thin-Film Heat Capacity Measurement
YU Jun1, TANG Zhen-An1, ZHANG Feng-Tian1, WEI Guang-Fen1, WANG Li-Ding2
1Department of Electronic Engineering, Dalian University of Technology, Dalian 116024
2School of Mechanic Engineering, Dalian University of Technology, Dalian 116024
Investigation of a Microcalorimeter for Thin-Film Heat Capacity Measurement
1Department of Electronic Engineering, Dalian University of Technology, Dalian 116024
2School of Mechanic Engineering, Dalian University of Technology, Dalian 116024
Abstract： A microcalorimeter is studied for testing heat capacity of thin films. The microcalorimeter is a suspended membrane supported by six microbridges, which is fabricated by the front-side surface micromachining. Compared to the bulk micro-machined one, the microcalorimeter has excellent mechanical strength and precisely controlled pattern size as well as good thermal characteristics that are essential to a microcalorimeter. The heating rate of the microcalorimeter is up to 2×105K/s with 4.5mW heating power in vacuum, and the heat capacity of the corresponding empty microcalorimeter is about 23.4nJ/K at 300K. By a pulse calorimetry, the heat capacity of Al thin films with thickness of 40--1150nm are measured in the temperature range from 300K to 420K in vacuum. The mass of each sample is evaluated and the specific heat capacity is calculated. The results show that specific heat capacity of the 1150-nm Al film agrees well with the data of bulk Al reported in the literature. For the thinner films, enhanced heat capacity is observed.
2005, Vol. 22 
