High Resolution 4H-SiC p-i-n Radiation Detectors With Low-Voltage Operation

Abstract

The results of electrical characteristics and alpha-particle energy spectrometry of 4H-SiC p-i-n diodes are reported. From the capacitance-voltage measurement, the effective doping concentration of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$80 ~\mu \text{m}$ </tex-math></inline-formula> lightly doped 4H-SiC epitaxial layer used in this work is calculated to be about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 10\,\,^{{13}}$ </tex-math></inline-formula> cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{3}}$ </tex-math></inline-formula> , approaching the limit of the lowest doping level by the SiC epitaxial growth technique. The detector exhibits consistently low leakage current of picoampere level at a reverse bias of 100 V and superior thermal stability up to 150 °C. Resultantly, an energy resolution of 0.6% has been achieved within a 5486 keV <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula> -particle spectrum, which is comparable to the high-resolution SiC Schottky barrier <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula> -particle detector. Also, near 100% charge collection efficiency has been realized with reverse bias exceeding 25 V. This study thus provides a promising solution to high-performance 4H-SiC radiation detectors with low-voltage operation.

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