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

Abstract

Deep-level transient spectroscopy (DLTS) and Laplace-DLTS were used to investigate the effect of alpha-particle irradiation on the electrical properties of nitrogen-doped 4H-SiC. The samples were bombarded with alpha-particles at room temperature (300 K) using an peaks at E C -(0.55-0.70) eV (known as Z 1 /Z 2 ) were attributed to an isolated carbon vacancy (V C ).

Electrical characterization of electron irradiated and annealed lowly-doped 4H-SiC

“…The effect of annealing on levels E 0.12 and E 0.18 was not noticeable due to the low concentration of the defects while level E 0.10 which had been completely suppressed by irradiation showed recovery after annealing at 500 °C. The reason why irradiation suppresses this level with a reversal from annealing has been reported earlier by Omotoso et al [31].…”

“…This defect appeared as a shoulder of E 0.69 on the high temperature side. The structure of this defect has not been reported in literature despite its presence having been reported after alpha-particle, electron and proton irradiation [27,30,31]. However, since this defect is introduced by irradiation, it is possibly generally related to carbon vacancies, silicon vacancies, carbon or silicon interstitials, carbon or silicon antisites or complexes of these possibilities.…”

Electrical charge state identification and control for the silicon vacancy in 4H-SiC

“…Interestingly, the S1 DLTS peak accommodates contributions from two distinct defect centers, 39 as revealed by the Laplace-DLTS spectra (see Supplementary Methods 2 for details) in Fig. 4b.…”

Laplace DLTS study of deep defects created in neutron-irradiated n-type 4H-SiC

“…As already mentioned, irradiations and ion implantations performed at sufficiently high energies for displacement of silicon atoms could potentially introduce additional deep levels in DLTS spectra overlapping with deep levels related to carbon displacement. In the case of alpha particle irradiation a peak which overlaps with EH1 has been observed in DLTS spectrum [20].…”

“…The assignment of other commonly observed deep levels in irradiated n-type 4H-SiC is still uncertain and only speculations are possible with the available data. Two deep levels usually labeled as S1/S2 [11,12], S2/S4 [13,14] or EH1/EH3 [15][16][17][18] with energies around E C -0.4 eV and E C -0.7 eV [19,20] can be observed in n-type 4H-SiC after electron or proton irradiation and ion implantation. These defects are introduced by low energy electron irradiation which displaces only the carbon atom in the 4H-SiC crystal lattice [15].…”