Investigation of a distribution function suitable for acceptors in SiC

The distribution function suitable for an acceptor in p-type SiC is investigated using lightly or heavily Al-doped SiC samples. From the temperature dependence of the hole concentration, the density and energy level of the acceptors are estimated using two different distribution functions. The proposed distribution function, which considers the influence of the excited states of acceptors, can be applied to both the samples, while the Fermi-Dirac distribution function, which does not include this influence, can be applied only to the lightly doped sample. In order to elucidate this result theoretically, the dependencies of both distribution functions on the temperature or the acceptor density are simulated. From these simulations, the proposed distribution function is found to be appropriate for determining the density and energy level of dopants with a deep dopant energy level for any dopant density. (C) 2004 American Institute of Physics.