  Integrated circuits (ICs) that can operate at high temperature have a wide
variety of applications in the fields of automotive, aerospace, space
exploration, and deep-well drilling. Conventional silicon-based complementary
metal-oxide-semiconductor (CMOS) circuits cannot work at higher than 200
$^\circ$C, leading to the use of wide bandgap semiconductor, especially silicon
carbide (SiC). However, high-density defects at an oxide-SiC interface make it
impossible to predict electrical characteristics of SiC CMOS logic gates in a
wide temperature range and high supply voltage (typically ${\geqq 15}$ V) is
required to compensate their large logic threshold voltage shift. Here, we show
that SiC complementary logic gates composed of p- and n-channel junction
field-effect transistors (JFETs) operate at 300 $^\circ$C with a supply voltage
as low as 1.4 V. The logic threshold voltage shift of the complementary JFET
(CJFET) inverter is 0.2 V from room temperature to 300 $^\circ$C. Furthermore,
temperature dependencies of the static and dynamic characteristics of the CJFET
inverter are well explained by a simple analytical model of SiC JFETs. This
allows us to perform electronic circuit simulation, leading to superior
designability of complex circuits or memories based on SiC CJFET technology,
which operate within a wide temperature range.
