Performance and Understanding of 4H-SiC Electron Devices at Low Temperature Range

In this paper, we propose the potentiality and the limiting factors of 4H-SiC devices operating at low temperature, i.e. down to 200K. The main physical properties are analyzed in low temperature regime with a focus on bipolar diodes and, in particular, on lateral pin diodes integrated in 4H-SiC CMOS circuits. Moreover, for the first time an early analysis of the electrical characteristics of 4H-SiC lateral <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$p^{+}-p-n^{+}$</tex> diodes from 300K down to 175K is shown. The analysis shows a generation-recombination current with an ideality factor higher than 2, which is ascribed to the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Z_{1/2}$</tex> defect between 200K and 175K and to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$E_{6/7}$</tex> defect between 225K and 300K, instead a significative increase of the series resistance has been observed. The activation energy of such series resistance is 183meV and it is not related to the recombination of injected free carriers, but it can be ascribed either to an ohmic contact limitation mechanism or to a further recombination of the injected free carriers in the p-well region.