Depth profiles of electron and hole traps generated by reactive ion etching near the surface of 4H-SiC

• Published in: Journal of applied physics 2024-09, Vol.136 (9)
• Main Authors: Kozakai, Shota, Fujii, Haruki, Kaneko, Mitsuaki, Kimoto, Tsunenobu
• Format: Article
• Language: English
• Subjects: Bulk density; Conduction bands; Deep level transient spectroscopy; Defect annealing; Depth profiling; Electron traps; Hole traps; Reactive ion etching; Schottky diodes; Silicon carbide; Valence band
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/5.0221700

Deep levels in the whole bandgap of 4H-SiC generated by reactive ion etching (RIE) are investigated with both n- and p-type SiC Schottky barrier diodes by deep-level transient spectroscopy (DLTS). Depth profiles of the observed deep levels were analyzed using the DLTS peak intensities at various bias voltages and numerical calculations. The major electron traps detected after RIE and subsequent annealing at 1300  °C include the Z 1 / 2 ( E C − 0.66 eV), ON1 ( E C − 0.88 eV), ON2 ( E C − 0.95 eV), and EH 6 / 7 ( E C − 1.50 eV) centers, and the major hole traps include the UK1 ( E V + 0.51 eV), UK2 ( E V + 0.72 eV), HK0 ( E V + 0.77 eV), HK2 ( E V + 0.79 eV), and HK3 ( E V + 1.31 eV) centers, where E C and E V denote the conduction and valence band edges, respectively. Most of the traps were localized near the surface (2  μm). By annealing at 1400  °C, most of the hole traps were eliminated, but several electron traps remained. From these results, the origins of these defects are discussed.