Evaluation of n-type doping of 4H-SiC and n-/p-type doping of 6H-SiC using absorption measurements

• Published in: Materials science & engineering. B, Solid-state materials for advanced technology Vol. 80; no. 1; pp. 352 - 356
• Main Authors: Wellmann, P.J., Bushevoy, S., Weingärtner, R.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 22.03.2001; Elsevier
• Subjects: Absorption measurement; Charge carrier concentration; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Defects and impurities in crystals; microstructure; Doping and impurity implantation in other materials; Exact sciences and technology; Mapping; Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity); Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics; Silicon carbide; Structure of solids and liquids; crystallography; Absorption measurement; Mapping; Silicon carbide; Charge carrier concentration; Inorganic compounds; Semiconductor materials; Impurities; Polytypism; Doping; Silicon carbides; Numerical method; Absorption spectra; Experimental study; Effective mass model; Carrier density
• ISSN: 0921-5107; 1873-4944
• DOI: 10.1016/S0921-5107(00)00598-5

A non-destructive, absorption measurement based optical method has been developed in order to determine doping type (n- or p-type), doping level and doping level distribution in 4H and 6H silicon carbide (SiC) wafers. The bandgap absorption has been calculated numerically taking into account band filling, band shrinkage and band tailing effects which are a function of donor and acceptor concentration N D and N A, respectively. The numerical results are compared with experimental data. A calibration plot of the doping dependence of the absorption of n-type 6H SiC is presented and the application for mapping of the SiC wafer doping level distribution is demonstrated.