A simplified thermal model for lateral MOSFET and its application to temperature monitoring

• Published in: Semiconductor science and technology 2014-09, Vol.29 (9), p.95017
• Main Authors: Carvajal, M A, Martínez-García, M S, Martínez-Olmos, A, Banqueri, J, Palma, A J
• Format: Article
• Language: English
• Subjects: MOSFET; temperature sensor; thermal model
• ISSN: 0268-1242; 1361-6641
• DOI: 10.1088/0268-1242/29/9/095017

This work presents a novel model to describe the thermal dependence of source-drain voltage of metal-oxide-semiconductor field-effect transistors (MOSFETs) in saturation regime, justified and experimentally tested in n-channel and p-channel transistors. This model provides the temperature coefficient of source-drain voltage as a function of transistor parameters and the drain current as a compact, static dc and empirical model. To do so, an exhaustive thermal characterization of p-channel MOSFET (pMOS) 3N163 (Vishay Siliconix, USA) and n-channel MOSFET (nMOS) 3N170 (Linear Systems, USA) was carried out in the industrial temperature range of −40 °C to 85 °C. Experimental results are in agreement with the proposed thermal model in different current ranges depending on the transistor model, from 15 A to 700 A for 3N163 and from 200 A to 5 mA for 3N170. Finally, the thermal model was applied to design a temperature sensor based on differential measurements of source-drain voltages in a pair of complementary MOSFETs, achieving an average sensitivity of 5.17 ± 0.13 mV °C−2, with a maximum linearity error of 1.1% for the industrial temperature range. This temperature sensor based on MOSFETs offers high sensitivity with a low number of devices and possible compatibility with current manufacturing processes.