Influence of Triangle Structure Defect on the Carrier Lifetime of the 4H-SiC Ultra-Thick Epilayer

Abstract

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 1.34 μs 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.

Morphological and microstructural analysis of triangular defects in 4H-SiC homoepitaxial layers

“…However, the peak at 540 nm indicated the presence of 3C-SiC. 30 In addition, there were multiple etch pits at positions 2 and 3. A new peak appears at 424 nm in the PL spectra due to extrinsic (single extra layer) Frank-type stacking faults (SFs) in the epilayer.…”

Surface defects in 4H-SiC: properties, characterizations and passivation schemes

“…Figure 13(a) reveals an optical image of an SiC wafer with many triangle defects. Its lifetime mapping and PL mapping are illustrated in figures 13(b) and (c) [59]. It is evidently demonstrated that the region of triangle defects has lower minority carrier lifetime and PL counts, particularly at the edge of the SiC wafer.…”

Multiple-Layer Triangular Defects in 4H-SiC Homoepitaxial Films Grown by Chemical Vapor Deposition

“…Furthermore, a large portion of these TDs exhibit characteristics similar to comet defect or other defects in the triangular region of TDs [19]. The projection length L of these surface morphological defects like TDs along the [11][12][13][14][15][16][17][18][19][20] direction satisfies the equation:…”

“…The surface morphology of TDs contains two edges. The triangular head sometimes has an obvious small triangular dent or falling object, and the triangular area in the defect is depressed downward [20].…”

“…The study of multiple-layer structures on other materials provides a theoretical approach to the study of this triangular defect and elucidates the causes of the defect [21,22]. The projection length L of these surface morphological defects like TDs along the [11][12][13][14][15][16][17][18][19][20] direction satisfies the equation:…”