Electrical Properties of Mg-Implanted 4H-SiC

Abstract

Because Al and B (elements of III group) in SiC are deep-level acceptors and these acceptors cannot reduce the resistivity of p-type SiC very much, Mg (element of II group) that may emit two holes into the valence band is investigated. A p-type 4H-SiC layer is obtained by 1800 °C annealing of the Mg-implanted layer, not by 1600 and 1700 °C annealing. It is found that a Mg acceptor level in 4H-SiC is too deep to determine the reliable 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 including the influence of the excited states of the Mg acceptor, therefore, its density and energy level can be determined to be approximately 1×1019 cm-3 and 0.6 eV, respectively. Judging from the Mg implantation condition, the obtained values are considered to be reliable.