An analytical two-dimensional model is developed to explain the minority-carrier exclusion effect in circular spreading-resistance temperature (SRT) sensor fabricated on thin silicon film. The model can be used to show the relation between minority-carrier exclusion length and maximum operating temperature of the sensor under different bias currents and different doping levels. Comparison is made between the proposed model and the conventional one-dimensional model used for similar sensors with rectangular shape. Experimental results show that the new model is more accurate than the one-dimensional model for predicting the characteristics of the circular SRT sensor. (C) 2004 Elsevier Ltd. All rights reserved.