Bulletin of Electrical Engineering and Informatics Vol. 12, No. 5, October 2023, pp. 2784~2793 ISSN: 2302-9285, DOI: 10.11591/eei.v12i5.5283  2784 Journal homepage: http://beei.org Study of the thermal drifts on the piezoresistivity using mobility model and finite difference method of electric heater Abdelaziz Beddiaf 1,2 , Fouad Kerrour 2 1 Department of Electrical Engineering, Abbes Laghrour University, Khenchela, Algeria 2 Laboratory of Renewable Energy Devices Modeling and Nanoscale MODERNA, Department of Electronics, University of Constantine 1, Constantine, Algeria Article Info ABSTRACT Article history: Received Nov 18, 2022 Revised Feb 23, 2023 Accepted Mar 15, 2023 In pressure sensors, four piezoresistors connected in a Wheatstone bridge are often provided with a voltage varying between 5 and 10 V. Unfortunately, this voltage is a source of drifts created by electric heating. This study focuses on the internal heating and piezoresistive effect of piezoresistors represented by the variation of their resistivity. To do this, we use the finite difference method (FDM) to solve the heat transfer equation, taking into account the conduction in Cartesian coordinates for the variable regime. We examine how the temperature affects the piezoresistivity in these sensors when the potential is applied. In this case, the variation of the temperature has been calculated as a function of applied voltage, as well as for the operating time of the sensor. Furthermore, the evolution of resistivity over time was determined for several geometric properties of the membrane using the mobility model. This was established for different doping levels. Additionally, the change in resistivity due to the application of voltage was evaluated. It was observed that resistivity is greatly affected by the temperature rise produced by the applied voltage when the device is actuated for a prolonged time. Consequently, this results in drifting in the output response of the sensor. Keywords: Finite difference method Mobility Piezoresistivity Sensors Voltage This is an open access article under the CC BY-SA license. Corresponding Author: Abdelaziz Beddiaf Department of Electrical Engineering, Abbes Laghrour University 40000 Khenchela, Algeria Email: beddiafaziz@yahoo.fr 1. INTRODUCTION Many domains that require the use of piezoresistive sensors with excellent reliability such as industry and biomedical due to their good linearity of output voltage, excellent compatibility with microelectronic systems and some other advantages [1]–[4]. However, they often suffer from the thermal drift. The study of electric heater effect in these sensors types is important to optimize the output characteristics drift [5]–[8]. As a result, several previous research papers have been carried out in this domain in order to lessen this effect, when the bridge is powered by an electric tension. Research by Ansari and Cho [7] was to derives both temperature independent and dependent models for temperature rise created by bias voltage in piezoresistive microcantilevers. Their approach is based on analytical model in steady state for describing the temperature diffusion in microcantilever by self heating [7]. Research by Aryafar et al. [9] introduce a novel technique for temperature compensation of piezoresistive pressure sensors. In their technique, additional silicon resistors with negative temperature coefficient of resistivity are used for compensation purpose. More recently, Tian et al. [10] have developed an analytical model of temperature characteristics in pressure sensor to investigate the influence factors of temperature zero drift,