Recombination centers in 4H-SiC investigated by electrically detected magnetic resonance and ab initio modeling

Abstract

Electrically detected magnetic resonance (EDMR) is a powerful technique for the observation and categorization of paramagnetic defects within semiconductors. The interpretation of the recorded EDMR spectra has long proved to be challenging. Here, defect spectra are identified by comparing EDMR measurements with extensive ab initio calculations. The defect identification is based upon the defect symmetry and the form of the hyperfine (HF) structure. A full description is given of how an accurate spectrum can be generated from the theoretical data by considering some thousand individual HF contributions out of some billion possibilities. This approach is illustrated with a defect observed in nitrogen implanted silicon carbide (SiC). Nitrogen implantation is a high energy process that gives rise to a high defect concentration. The majority of these defects are removed during the dopant activation anneal, shifting the interstitial nitrogen to the desired substitutional lattice sites, where they act as shallow donors. EDMR shows that a deep-level defect persists after the dopant activation anneal. This defect is characterized as having a gc∥B=2.0054(4) and gc⊥B=2.0006(4), with pronounced hyperfine shoulder peaks with a 13 G peak to peak separation. The nitrogen at a carbon site next to a silicon vacancy (NCVSi) center is identified as the persistent deep-level defect responsible for the observed EDMR signal and the associated dopant deactivation.

Electrically active induced energy levels and metastability of B and N vacancy-complexes in 4H–SiC

“…The so called NV centre (N C V Si ) in 4H-SiC is a well known defect, which has been extensively studied [2,19,20]. In this article, we have reported a few findings about the NV centre in 4H-SiC which are in agreement with earlier reports.…”

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

“…The EDMR method is a well established technique to identify paramagnetic defect centers in semiconductors and has successfully been used for the identification of defects in fully processed SiC devices. 19,25 EDMR is related to EPR and takes advantage of the fact that a portion of the current through a semiconductor device may be spin dependent. 26 In this work, spin dependent recombination (SDR) was measured.…”

“…The number of individual lines can be very high but there is an efficient method to generate an accurate spectrum from known HF parameters of the nuclei involved, as described in a related study. 25 In this approach the total spectrum is The P bC center is well characterized in an EPR study on oxidized porous SiC by J.L.…”

“…4. The simulated spectra of the basal P bC and V Si were generated by the computer code described in a related study 25 using the HF data from the literature. 9,33 The spectrum contains two pairs of lines symmetric around the center line.…”

Coherent electrical readout of defect spins in silicon carbide by photo-ionization at ambient conditions

“…Traditionally, interest in defects in SiC was driven by their impeding properties to high power electronic devices 26 . This has initialized a wealth of studies utilizing electron paramagnetic resonance 27,28 and electrically detected magnetic resonance 29–33 . Among many investigated phenomena, spin dependent recombination has been shown to allow for self-calibrating magnetometers in a non-coherent fashion 34 .…”