A Temperature Independent Effect of Near-Interface Traps in 4H-SiC MOS Capacitors

Abstract

In this paper we report temperature independent near-interface traps (NITs) in the gate oxide of N-type MOS capacitors. The measurements were performed by a recently developed direct-measurement technique, which detected NITs with energy levels between 0.13 eV to 0.23 eV above the bottom of conduction band. These traps are also spatially localized close to the SiC surface, as evidenced by the fact that they are not observed at measurement frequencies below 6 MHz. The temperature independence indicates that this localized defect is different from the usually observed NITs whose density is increased by temperature-bias stress.