Electroluminescence Spectral Imaging of Extended Defects in 4H-SiC

Abstract

To understand the nature of various extended defects and their impact on the electronic or optoelectronic characteristics of semiconductor devices, the investigation of spectral properties is required. However, electroluminescence spectroscopy does not provide spatial or structural information. The lack of such information can lead to incorrect assignment of a luminescence band and therefore misinterpretation of the nature of the emitting defect. Here we report on the collection and analysis of real-color and spectrally selective monochromatic electroluminescence (EL) images from 4H-SiC PiN diodes. The former provides the approximate spectral properties from the color of the various defects with high spatial resolution, while the latter enables simultaneous collection of both structural and spectral properties from extended defects, thereby assisting in providing the correct assignment of the various spectral features observed. This effort enabled the observation of the formation of a green EL emission located at C-core partial dislocations (PDs) that occurred during the stacking fault (SF) expansion process.

(Invited) Mitigating Defects within Silicon Carbide Epitaxy

“…The first technique was initially reported by Liu et al (12,60,61) and utilized the differences in the photo-and electroluminescence emission spectra of TSDs and TEDs at low injection levels. He determined that while both appear as a single point within EL/PL images, the incorporation of band-pass filters can effectively isolate either the ~600 or ~800-850 nm emission lines of the TEDs and TSDs, respectively.…”

Luminescence Imaging of Extended Defects in SiC via Hyperspectral Imaging

“…Currently, such characterization is typically performed through the use of electro-(EL) and photoluminescence spectroscopy or imaging. However, while imaging provides a broad spatial view, enabling the observation of a large number of defects within the field of view, minimal or no spectral information is obtained [3,4]. In the case of spectroscopic methods, the spot size used is either quite broad (100's µm to a couple mm's) so that no spatial information is obtained and signatures from small defects can be lost in the background (e.g.…”

“…For electroluminescence (EL) measurements, obtaining spectral information from specific extended defects is quite difficult and is typically acquired with very low spectral resolution [4]. Here, we report on the use of hyperspectral imaging for the simultaneous collection of spectral and spatial information over a user defined field-of-view.…”

Nanoscale Infrared Spectroscopic Characterization of Extended Defects in 4H-Silicon Carbide

“…IGSFs occur during the crystal growth process, and in contrast to the more broadly investigated RISFs, 20 various factors, such as residual strain at the substrate present during growth, 21,22 contact with the walls of the growth chamber, and presence of particulates or Si droplets on the substrate surface. 16 Previous characterization of IGSFs has been performed using methods such as optical beam-(OBIC) 19 and electron beam-induced current (EBIC) 23 mapping, cathodoluminescence, 24 electroluminescence, 25 and photoluminescence imaging, 26 as well as transmission electron microscopy. 27 Here, we have chosen to investigate an IGSF structure within a 4H-SiC epitaxial layer to explore the potential of nano-FTIR for the characterization of extended defects within WBG semiconductors.…”

“…The formation of IGSFs has been attributed to various factors, such as residual strain at the substrate present during growth, , contact with the walls of the growth chamber, and presence of particulates or Si droplets on the substrate surface . Previous characterization of IGSFs has been performed using methods such as optical beam- (OBIC) and electron beam-induced current (EBIC) mapping, cathodoluminescence, electroluminescence, and photoluminescence imaging, as well as transmission electron microscopy …”