Electrical Behavior of Mg in Mg-Implanted 4H-SiC Layer

Abstract

Because Al and B (elements of group III) in SiC are acceptors with deep energy levels and these acceptors cannot reduce the resistivity of p-type SiC very much, Mg (an element of group II) that may emit two holes into the valence band is investigated. Annealing at 1800 ◦C makes a Mg-implanted layer p-type. It is found that an Mg acceptor level in 4H-SiC is too deep to reliably determine the density and energy level of the Mg acceptor using the frequently used occupation probability, i.e., the Fermi Dirac distribution function. Using the distribution function that accounts for the in uence of the excited states of a deep-level acceptor, the density and energy level of Mg acceptors can be determined to be approximately 1× 10 cm−3 and 0.6 eV, respectively. These values are considered to be reliable because they agree well with the Mg implantation condition.