Effect of triangle structure defects in a 180-μm-thick as-grown n-type 4H-SiC homoepitaxial layer on the carrier lifetime is quantitatively analyzed,which is grown by a horizontal hot-wall chemical vapor deposition reactor.By microwave photoconductivity decay lifetime measurements and photoluminescence measurements,the results show that the average carrier lifetime of as-grown epilayer across the whole wafer is 2.59 μs,while it is no more than 1.34μs near a triangle defect (TD).The scanning transmission electron microscope results show that the triangle structure defects have originated from 3C-SiC polytype and various types of as-grown stacking faults.Compared with the as-grown stacking faults,the 3C-SiC polytype has a great impact on the lifetime.The reduction of TD is essential to increasing the carrier lifetime of the as-grown thick epilayer.