Witold J. Stepowicz

Functional and catastrophic thermal failures in bipolar electronic circuits

In semiconductor devices interactions between electrical and thermal effects result from the selfheating phenomenon. Due to selfheating and non-ideal heat transfer from a device to surroundings, the junction (inside) temperature rise above the ambient temperature is observed, and as a result the form of the d.c. characteristics of devices can be essentially changed. This temperature rise can lead to functional failure of the circuit in which the device is used, or to catastrophic failure of the device. In the paper some examples of such circuits as the transistor switch and the differential pair are described.

Thermal performance of LSCO and LSFO films for IR detectors

Bolometers are widely used as thermal detectors, e.g. in thermovision, medicine, astronomy etc. Among them there are thermistor-like devices consisting of the absorbing radiant power thermally sensitive films, deposited on the substrate. To meet the requirements made for bolometers, their material should have adequate parameters and characteristics. In this paper some thermal characteristics and parameters of the conducting, perovskite type ABO3 non-stoichiometric oxides LSCO and LSFO are discussed to evaluate their usefulness in the construction of bolometers.

Thermal resistance measurements of microwave devices

Temperature influences strongly the electrical behaviour of semiconductor devices, affecting their d.c. characteristics as well as small and large-signal parameters. To determine the junction temperature under thermal steady-state conditions, its thermal resistance has to be known. This paper describes briefly the experimental set-up and procedures developed at the GMA which permit such characterisation of various semiconductor devices including microwave types. As shown in the experimental example, high sensitivity and accuracy of the presented method enables comparative measurements, yielding the thermal resistance value of microwave planar mounting structures.