Impact of Carrier Lifetimes on Non-Destructive Mapping of Dislocations in 4H-SiC Epilayers

Abstract

Dislocations in 4H-SiC epilayers were imaged nondestructively by means of micro photoluminescence (-PL) mapping at room temperature. The one-to-one correspondence between the individual dislocations and the -PL mapping contrast has been consistently obtained. By analyzing the reduction of the intensity in the -PL mapping image performed at 390 nm (near band-edge emission), we were able to distinguish threading screw dislocations and threading edge dislocations. Furthermore, the contrast of dislocations in PL-intensity mapping image greatly depends on the carrier lifetimes of the 4H-SiC epilayers. Lifetimes longer than 0.5 s are essential to obtain a discernible contrast for the individual dislocations.