SURFACE AND INTERFACE DEPLETION CORRECTIONS TO FREE CARRIER-DENSITY DETERMINATIONS BY HALL MEASUREMENTS

Errors in the determination of (ND-NA) for semiconductor epitaxial layers by the Hall method can result if corrections for carrier depletion are omitted in the calculations. Simple practical procedures are discussed to correct for carrier depletion that occurs in epitaxial layers at their free surfaces, and their interfaces with semi-insulating substrates. Theoretical estimates of carrier depletion in GaAs indicate that depletion regions can extend several microns into high purity epitaxial layers, and can cause (ND-NA) to be considerably underestimated. Experimental evidence is presented in support of the theory. © 1979.