Compensation ratios in high-purity InP using an improved Hall measurement technique

Temperature-dependent Hall measurements were conducted on several high-purity n-type InP epitaxial layers grown by metalorganic chemical vapor deposition with the aim of clarifying the relationship between the 77-K Hall mobility, the free-carrier concentration, and the compensation ratio in high-purity InP. An improved method of Hall analysis for high-purity epitaxial layers was used which greatly reduces errors associated with depletion effects, as well as those associated with interfacial inhomogeneities in the growth direction. The method is essentially a modified version of the differential profiling method in which the difference between two successive Hall measurements, one before, and one after a controlled etch, is used to infer the properties of the portion of the epilayer removed during the etch. From curve fitting of the neutrality equation to the results of the temperature-dependent Hall measurements, the compensation ratios were estimated and compared to estimates obtained from previously reported calculations of the 77-K Hall mobility. The results are found to agree well with recently reported calculations for which the acoustic deformation potential and piezoelectric constant were assumed to be 6.5 eV and 0.01, respectively.