Study of deep levels in the Mg₂Si grown by vertical Bridgeman method

Abstract

The electrical characteristics of a Mg2Si p-n junction diode was investigated. The n-Mg2Si substrate was grown by using the vertical Bridgeman method. A p-n junction was fabricated by the thermal diffusion of Ag as an acceptor. The reverse current of the Au/Ag electrode diode was larger than that of the Ag electrode diode. The trap levels in the n-Mg2Si bulk crystal were investigated using deep-level transient spectroscopy. The magnitude of DLTS signal of E1 with the Au/Ag electrode diode was larger than that for the signals at the other trap levels. The E1 level corresponds to an Au-related trap that diffuses via thermal annealing during the alloying process. The open-circuit-voltage-decay study suggests the existence of a minority-carrier trap in n-Mg2Si. The minority-carrier lifetime was shorter for Au/Ag electrode diodes. Therefore, Au may be involved in the formation of minority-carrier traps, as well as in the formation of majority-carrier traps.