Influence of Oxide Processing on the Defects at the SiC-SiO&lt;sub&gt;2&lt;/sub&gt; Interface Measured by Electrically Detected Magnetic Resonance

Journal of Applied Physics

Cottom

Mészáros

et al. 2017

SiC based metal-oxide-semiconductor field-effect transistors (MOSFETs) have gained a significant importance in power electronics applications. However, electrically active defects at the SiC/SiO 2 interface degrade the ideal behavior of the devices. The relevant microscopic defects can be identified by electron paramagnetic resonance (EPR) or electrically detected magnetic resonance (EDMR). This helps to decide which changes to the fabrication process will likely lead to further increases of device performance and reliability. EDMR measurements have shown very similar dominant hyperfine (HF) spectra in differently processed MOSFETs although some discrepancies were observed in the measured g-factors. Here, the HF spectra measured of different SiC MOSFETs are compared and it is argued that the same dominant defect is present in all devices. A comparison of the data with simulated spectra of the C dangling bond (P bC ) center and the silicon vacancy (V Si ) demonstrates that the P bC center is a more suitable candidate to explain the observed HF spectra. a) gernot.gruber@alumni.tugraz.at 1 arXiv:1709.08664v1 [cond-mat.mtrl-sci]

Section: Discussionmentioning

confidence: 87%

Section: A Sample Descriptionmentioning

confidence: 92%

Section: A Sample Descriptionmentioning

confidence: 92%

Section: Comparison To Simulated Spectra Of the P Bc And V Simentioning

confidence: 99%

mentioning

confidence: 98%

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Electrically detected magnetic resonance of carbon dangling bonds at the Si-face 4H-SiC/SiO2 interface

Journal of Applied Physics

Cottom

Mészáros

et al. 2017

Impact of the NO Anneal on the Microscopic Structure and Chemical Composition of the Si‐Face 4H‐SiC/SiO₂ Interface

Gspan

Fisslthaler

et al. 2018

Adv Materials Inter

Self Cite

Understanding the microscopic structure of the SiC/SiO2 interface is crucial for the improvement of SiC based metal‐oxide‐semiconductor field‐effect transistors (MOSFETs). It is well established that interface states degrade the performance and reliability of SiC MOSFETs and that passivation can be achieved by anneals in NO‐containing atmospheres. However, the structural changes associated with the NO anneal and the improvement of the channel electron mobility are still not fully understood. In this study, the SiC/SiO2 interface of the state‐of‐the art 4H‐SiC n‐channel MOSFETs with a deposited oxide is extensively investigated with advanced scanning transmission electron microscopy (STEM) and spatially resolved electron energy‐loss spectroscopy (EELS) methods. The samples are treated with different postoxidation anneals (NO vs O2), resulting in strongly differing mobility and point defect density. The most notable structural difference between the samples is an increased N concentration located in the transition region between the SiC and the SiO2 of the NO‐annealed sample. The N signal is evenly distributed along the whole faceted interface and has a half‐width of wN = (1.8 ± 0.7) nm and an estimated areal density of cN = (4 ± 1) × 1014 cm−2. The observations support the idea that the N incorporation happens predominantly directly at the SiC/SiO2 interface where defect states are passivated.

Recombination defects at the 4H-SiC/SiO2 interface investigated with electrically detected magnetic resonance and ab initio calculations

Cottom

Journal of Applied Physics

Pobegen³

et al. 2018

The selectivity of electrically detected magnetic resonance (EDMR) is utilized to probe the dominant recombination defect at the Si-face 4H-SiC/SiO 2 interface. The nature of this defect has long been debated with the two main candidates being the Si vacancy (V Si) or the C-dangling bond (P bC). Through comparison between experimental EDMR measurements and ab initio calculations, an important performance limiting recombination defect observed with EDMR in the current generation of nMOSFETs is reasonably explained as a combination of the P bC and the dual-P bC defects. These defects match the symmetry, hyperfine interaction, and isotopic abundance observed in the experimental EDMR spectrum.