Nonmicropipe dislocations in 4H-SiC devices: electrical properties and device technology implications

摘要

It is well-knwon that SiC wafer quality deficiencies are delaying the realization of outstandingly superior 4H-SiC power electronics. While efforts to date have centered on eradicating micropipes (i.e., hollow core super-screw dislocations with Burgers vectors > 2c), 4H-SiC wafers and epilayers alos contain elementary screw dislocations (i.e., Burgers vector = 1c with no hollow core) in densities on the order to thousands per cm~2, nerly 100-fold micropipe densities. While not nearly as detrimental to SiC device performance as micropipes, it has been previously shown that diodes containing elementary screw dislocations exhibit a 5