4H-SiC-Based Low-Noise Front-End Charge Coupling Transistor for 0.9% Radiation Energy Resolution

This brief presents a wide bandgap SiC-based approach for the low-noise charge coupling transistor in the front-end electronic applications, demonstrating precise detection and energy resolution for the α-particles. With the joint construction techniques based on dual-gate epistructure design with alleviated capacitive coupling and charge leakage between the channel and the bottom gate, along with the etching damage repair and dry-wet-dry oxidation passivation fabrication process, 4H-SiC junction field-effect transistor (JFET) with room-temperature leakage of ~0.1 pA, input capacitance density as low as 0.285 fF/μm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sup>, and output conductance down to 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-<roman>6</roman></sup> S has been fabricated, achieving a preferable noise figure of 1.1 × 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-<roman>19</roman></sup> A<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sup>/Hz at 1 kHz. Meanwhile, the quiescent operation point has been well modulated with maximum transconductance tuned near zero gate bias, while the ON-to-OFF ratio reaches 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>10</roman></sup>. Correspondingly, the SiC JFET demonstrates excellent performance in the charge signal analysis with a standard error of 0.24%, and an energy resolution of 0.9% for the 5.4-MeV α-particle. This work thus paves a way for SiC-based front-end electronics in radiation detection applications.