A method for calculating the conductivity mobility spectrum using multi-carrier fitting

At low temperatures, ionized impurities are the dominant scattering mechanism limiting carrier mobilities in most semiconductors. Calculations of ionized impurity scattering have usually been based on the assumption that the ions scatter independently of one another. The purpose of this paper is to investigate the method of mobility calculation in which the carrier spectrum is found by solving the neutrality equation numerically. A development of the method, which allows calculation of the temperature dependent mobility spectrum of all carriers used in the neutrality equation for the GaAs/GaAs sample is presented. In order to explain the transport properties the following topics are discussed: • Theoretical calculation of the n-type GaAs transport parameters. • Comparison between measured and calculated values of the conductivity and Hall concentration, resistivity, conductivity and Hall mobility. • The values of conductivity mobility for each carrier transport component. • Application of the method for characterization of n-GaAs on SI GaAs MBE epi-layers. The new method allows for determination of the carrier mobility spectrum and is applied to GaAs/SI-GaAs layers in which the Hall voltage is magnetic field dependent.