| The primary focus of this dissertation was on the short term reliability of a thin film resistance temperature detector (RTD). As a first step, the transient and steady state temperature response of an encapsulated, thin-film RTD, which was used as a micro heater, have been characterized for a range of pressures and applied voltages, while placed on thermally insulating and conductive platforms. A user-friendly model was used to capture the three major mechanisms of heat transfer from the device (i.e. conduction, convection, and radiation). The calibration parameters of the model allowed the different modes of heat transfer to be quantified. The model correctly captures the fact that the conductive heat losses from the RTD to the underlying platform are far more dominant than the heat lost due to convection/conduction to the environment, the latter being 20% of the former. The experiments demonstrate, and the model captures, the fact that the radiative losses to the environment are almost identical in intensity as the convective/conductive losses to the environment from the RTD.;The next phase of the research focused on the short-term reliability of the RTD when used as a micro heater, and when subjected to various environmental and experimental conditions. The following tests were carried out: (i) determination of the upper temperature limit of the RTD (burn-in tests), (ii) determination of the cyclic temperature response until failure, at both a low pressure and at atmospheric pressure (cyclic tests), (iii) determination of the effects on the electrical characteristics and the temperature response of the RTD after having been soaked in a corrosive saline solution and also de-ionized water (soak tests). The causes of failure for the burn-in tests, as well as the cyclic tests were addressed and discussed. |
