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

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
$80 ~\mu \text{m}$
lightly doped 4H-SiC epitaxial layer used in this work is calculated to be about
$2\times 10\,\,^{{13}}$
cm
$^{-{3}}$
, 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
$\alpha $
-particle spectrum, which is comparable to the high-resolution SiC Schottky barrier
$\alpha $
-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.