Lateral depletion-mode 4H-SiC n-channel junction field-effect transistors operational at 400 °C*

Abstract

This paper presents the development of lateral depletion-mode n-channel 4H-SiC junction field-effect transistors (LJFETs) using double-mesa process toward high-temperature integrated circuit (IC) applications. At room temperature, the fabricated LJFETs show a drain-to-source saturation current of 23.03 μA/μm, which corresponds to a current density of 7678 A/cm2. The gate-to-source parasitic resistance of 17.56 kΩ ⋅ μm is reduced to contribute only 13.49% of the on-resistance of 130.15 kΩ ⋅ μm, which helps to improve the transconductance up to 8.61 μS/μm. High temperature characteristics of LJFETs were performed from room temperature to 400 °C. At temperatures up to 400 °C in air, it is observed that the fabricated LJFETs still show normally-on operating characteristics. The drain-to-source saturation current, transconductance and intrinsic gain at 400 °C are 7.47 μA/μm, 2.35 μS/μm and 41.35, respectively. These results show significant improvement over state-of-the-art and make them attractive for high-temperature IC applications.