60-700 K CTAT and PTAT Temperature Sensors with 4H-SiC Schottky Diodes

Razvan Pascu; Gheorghe Pristavu; Gheorghe Brezeanu; Florin Draghici; Philippe Godignon; Cosmin Romanitan; Matei Serbanescu; Adrian Tulbure

doi:10.3390/s21030942

60-700 K CTAT and PTAT Temperature Sensors with 4H-SiC Schottky Diodes

Sensors (Basel). 2021 Jan 31;21(3):942. doi: 10.3390/s21030942.

Authors

Razvan Pascu^{1

2

3}, Gheorghe Pristavu², Gheorghe Brezeanu², Florin Draghici², Philippe Godignon⁴, Cosmin Romanitan¹, Matei Serbanescu², Adrian Tulbure⁵

Affiliations

¹ National Institute for Research and Development in Microtechnologies-IMT Bucharest, 126A, Erou Iancu Nicolae Street, 077190 Bucharest, Romania.
² Faculty of Electronics, Telecommunications and Information Technology, University "Politehnica" of Bucharest, 060042 Bucharest, Romania.
³ Romanian Young Academy, Research Institute of the University of Bucharest, University of Bucharest, 030018 Bucharest, Romania.
⁴ Centre Nacional de Microelectrònica, CNM-CSIC, 08193 Barcelona, Spain.
⁵ Department of Informatics, Mathematics and Electronics, Faculty of Exact Sciences and Engineering, University "1 Decembrie 1918" of Alba Iulia, No. 5, Gabriel Bethlen Street, 510009 Alba Iulia, Romania.

Abstract

A SiC Schottky dual-diode temperature-sensing element, suitable for both complementary variation of V_F with absolute temperature (CTAT) and differential proportional to absolute temperature (PTAT) sensors, is demonstrated over 60-700 K, currently the widest range reported. The structure's layout places the two identical diodes in close, symmetrical proximity. A stable and high-barrier Schottky contact based on Ni, annealed at 750 °C, is used. XRD analysis evinced the even distribution of Ni₂Si over the entire Schottky contact area. Forward measurements in the 60-700 K range indicate nearly identical characteristics for the dual-diodes, with only minor inhomogeneity. Our parallel diode (p-diode) model is used to parameterize experimental curves and evaluate sensing performances over this far-reaching domain. High sensitivity, upwards of 2.32 mV/K, is obtained, with satisfactory linearity (R² reaching 99.80%) for the CTAT sensor, even down to 60 K. The PTAT differential version boasts increased linearity, up to 99.95%. The lower sensitivity is, in this case, compensated by using a high-performing, low-cost readout circuit, leading to a peak 14.91 mV/K, without influencing linearity.

Keywords: SiC-Schottky diode; linearity; readout circuit; sensitivity; wide-range temperature sensor.

Abstract

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