Electrically active point defects in n-type 4H–SiC

Abstract

An electrically active defect has been observed at a level position of ϳ0.70 eV below the conduction band edge (E c ) with an extrapolated capture cross section of ϳ5ϫ10 Ϫ14 cm 2 in epitaxial layers of 4H-SiC grown by vapor phase epitaxy with a concentration of approximately 1ϫ10 13 cm Ϫ3 . Secondary ion mass spectrometry revealed no evidence of the transition metals Ti, V, and Cr. Furthermore, after electron irradiation with 2 MeV electrons, the 0.70 eV level is not observed to increase in concentration although three new levels are observed at approximately 0.32, 0.62, and 0.68 eV below E c with extrapolated capture cross sections of 4ϫ10 Ϫ14 , 4ϫ10 Ϫ14 , and 5ϫ10 Ϫ15 cm 2 , respectively. However, the defects causing these levels are unstable and decay after a period of time at room temperature, resulting in the formation of the 0.70 eV level. Our results suggest strongly that the 0.70 eV level originates from a defect of intrinsic nature. The unstable behavior of the electron irradiation-induced defects at room temperature has not been observed in the 6H-SiC polytype.

Response of Ni/4H-SiC Schottky barrier diodes to alpha-particle irradiation at different fluences

“…Table 3 shows the attributes of each defect. A defect similar to E 0.39 showing acceptor-like behaviour, was reported earlier after electron irradiation by Doyle et al [23]. From Fig.…”

Electrical characterization of deep levels created by bombarding nitrogen-doped 4H-SiC with alpha-particle irradiation

“…The defect labelled E 0.39 with energy, 0.39 eV below the conduction band emanated after the diode received a fluence of 4.1×10 11 alpha-particle-cm -2 from a 241 Am source. The level labelled E 0.39 has been attributed to silicon vacancy (V Si ) [19]. in curve (ii) are due to the same defect as the E 0.55 and E 0.67 in curve (iii).…”

“…The defect labelled E 0.76 obtained at higher temperature side of the measurements. The structure of defect E 0.76 has not been reported despite its presence after electron and proton irradiation [19,24].…”

“…? [19,24] Curve (i) is the spectrum of the as-grown sample and indicates the presence of four electron traps (E 0.09 , E 0.11 , E 0.16 and E 0.65 ) with energies 0.09, 0.11, 0.16 and 0.65 eV below the conduction band. These defects were associated with the growth of 4H-SiC.…”

Effects of 3-MeV Protons on 4H-SiC Bipolar Devices and Integrated OR-NOR Gates

“…Since annealing effects in irradiated SiC devices at room temperature after a period of several months have been reported [20], the measurements presented here were done at various occasions during a period of one week. For this time period, no change in data was found.…”