Fabrication of High Resolution n-type 4H-SiC Epitaxial Layer Alpha Particle Detectors, Defect Characterization and Electronic Noise Analysis
Electrical Engineering, Optics, Physics
In the present work high-resolution alpha particle detectors have been fabricated on high quality 20 μm thick n-type 4H-SiC epitaxial layers. Schottky barrier detectors have been fabricated by depositing 10 nm thick nickel contacts on the Si face of the epilayers. The detectors were characterized using current-voltage (I-V), capacitance-voltage (CV), alpha spectroscopic measurements, and deep level transient spectroscopy (DLTS). I-V measurements revealed a barrier height of ~1.6 eV, diode ideality factor of 1.09, and leakage current of the order of 14 pA at an operating bias of 110 V. C-V measurements revealed low effective doping concentrations of 3.1 × 1014 cm-3 in the epilayers. A micropipe density lower than 1 cm-2 was evaluated in the epilayers. Pulse-height spectroscopy exhibited energy resolution as high as 0.37 % for 5.48 MeV alpha particles with a detector active area of 11 mm2. A diffusion length of ~13.2 μm for holes has been determined in these detectors following a calculation based on a drift-diffusion model. Detailed electronic noise analysis in terms of equivalent noise charge (ENC) was carried out to study the effect of various noise components that contribute to the total electronic noise in the detection system. The noise analysis revealed that the white series noise due to the detector capacitance has substantial effect on the detector’s overall performance. DLTS measurements have revealed the presence of at least four majority (electron) carrier trap levels that can act as recombination/generation or trapping centers. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Published in Proceedings of SPIE, Volume 8852, 2013.
K. J. Zavalla, S. K. Chaudhuri, and K. C. Mandal, “Fabrication of high resolution n-type 4H-SiC epitaxial layer alpha particle detectors, defect characterization and electronic noise analysis.,” Proc. SPIE 8852, 88520D (2013).
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