Amplifier Based on 4H-SiC MOSFET Operation at 500 °C for Harsh Environment Applications

Successful operation of 4H-silicon carbide (SiC) MOSFET and integrated electronic circuit based on 4H-SiC MOSFET is reported at temperature up to
$500~^{\circ }\text{C}$
in air. The high-temperature operation of the integrated circuit (IC) based on 4H-SiC MOSFET strongly depends on the reliability of metal/SiC contact. Based on the transfer length method (TLM), the Ni/Nb/n-type 4H-SiC junction exhibits ohmic behavior with specific contact resistance of
$1.86\times 10^{-{4}}\,\, \Omega \cdot $
cm
²
when operating at
$500~^{\circ }\text{C}$
. In contrast, the voltage gain of the amplifier is strongly governed by the variation of carrier mobility of the 4H-SiC MOSFET when temperature varies from room temperature to
$500~^{\circ }\text{C}$
. The experimental results show that, when the temperature is increased from
$20~^{\circ }\text{C}$
to
$300~^{\circ }\text{C}$
, the amplifier gain of the IC increased from 23.8 to 153.0. Though the voltage gain decreases when the temperature increases above
$300~^{\circ }\text{C}$
, it is still higher than 50 at
$500~^{\circ }\text{C}$
. These results indicate that integrated electronic circuits based on this 4H-SiC MOSFET technology could be potentially used for harsh environment applications.