The silicon carbide industry has been expanding in the recent years, producing a search for SiC non‐contact electrical characterization methods capable of replacing the commonly used Hg‐probe technique. In this work we present doping metrology based on the corona‐Kelvin method, which was originally developed and used for silicon IC dielectric and interface characterization. The method employs corona discharge in air to deposit precise doses of charge on the SiC surface. The corresponding depletion voltage is then measured with a Kelvin probe enabling non‐contact determination of the static charge‐voltage and capacitance‐voltage characteristics. The approach incorporates three novel elements: 1. corona charging of SiC to high depletion voltage with constant surface potential method; 2. the derivative charge‐voltage measurements for d(1/C2)/dV analysis and doping profiling; 3. surface charge neutralization with appropriate SiC illumination for repeated measurements. We demonstrate excellent repeatability and accuracy of the novel approach for n and p‐type SiC doping measurements in a range from 1014cm‐3 to mid 1018cm‐3 and excellent correlation with results obtained with mercury‐probe C‐V. Using multi‐layer epitaxial SiC structures, we further demonstrate the effectiveness of novel non‐contact depth profiling. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

We present a refined non-contact doping density determination in silicon carbide that incorporates 3 novel features: (1) constant surface potential method of corona charging into depletion; (2) vibrating Kelvin probe measurement of depletion surface voltage and voltage compensation maintaining constant surface potential, and (3) a unique self-consistent procedure for data analysis. The results obtained on epitaxial SiC demonstrate up to 3 times improved accuracy and enhanced repeatability giving 1σ in 10 repeats of 0.05% and 0.1% for doping in e15cm-3 and e19cm-3 range, respectively. An enhanced charging range enables measurement of high doping density in the e19cm-3 range and to achieve larger depth in doping profiling. With these refinements, a non-contact doping metrology for SiC represents an industry ready alternative to Hg-CV.