Forward-current-generated donor centers in high-voltage 4H-SiC based p-i-n diodes

Abstract

High-voltage diodes based on silicon carbide of 4H polytype (4H-SiC) have been studied by the deep-level transient spectroscopy (DLTS) method. It is established that the passage of forward current leads to the activation of a donor center with an activation energy of Ec − 0.2 eV and an electron capture cross section of σn ∼ 2.0 × 10−15 cm2. The DLTS measurements reveal the appearance of this center upon the transfer of a very small charge through the diode, under the conditions where the forward voltage drop on the diode remains almost unchanged. A possible nature of the observed phenomenon is discussed.