Interaction of Radiation‐Induced Self‐Interstitials with Vacancy‐Oxygen Related Defects V_nO₂ (n from 1 to 3) in Silicon

Abstract

Two stage electron irradiation with thermal heat‐treatments after each stage is used for vacancy‐oxygen‐related defect engineering in Czochralski‐grown silicon (Cz‐Si). The Cz‐Si samples are first irradiated at room temperature with 2.5 MeV electrons and then heat‐treated at 320 °C to anneal out the VO, V2O, and V3O centers and generate the VO2, V2O2, and V3O2 complexes as the dominant vacancy‐oxygen‐related defects. Subsequently, the samples are irradiated at room temperature again and subjected to 30‐min isochronal annealing in the temperature range 75–350 °C. Defect evolution upon the treatments is monitored by means of the local vibrational mode (LVM) absorption spectroscopy. From an analysis of changes in intensity of the LVM lines it is revealed that the second irradiation results in a noticeable decrease in the concentrations of the VO2, V2O2, and V3O2 complexes and an increase in the concentrations of the oxygen dimer and the VO2* defect (metastable state of VO2, which consists of the VO and Oi components). The observed defect transformations are argued to be related to interactions of the radiation‐induced self‐interstitial silicon atoms (I) with the vacancy‐oxygen complexes via the following reactions: VO2 + I → O2i, V3O2 + I → V2O2, V2O2 + I → VO2*.

Comparative Study of Oxygen- and Carbon-Related Defects in Electron Irradiated Cz–Si Doped with Isovalent Impurities

“…We observed numerous signals from O-related and C-related defects. Regarding O-related defects, there were well-known bands [9][10][11][12][13][14][15][127][128][129][130][131] such as those of VO n (n = 1-5) defects: VO (830 cm −1 ), VO 2 (888 cm −1 ), VO 3 (904, 968, 1000 cm −1 ), VO 4 (985, 1010 cm −1 ), VO 5 (1037, 1051 cm −1 ), and some very weak bands originating [102,127] from either VO 6 or V n O m and VO n C defects (762, 967, 1005 cm −1 , respectively). Notably, the 762 cm −1 band appeared clearly only in the higher fluence irradiated samples.…”

“…In the case of Si, O and C are the two main impurities incorporated into the lattice during growth. Both are electrically inactive, but during irradiation and subsequent anneals at various temperatures they lead to the formation of a number of oxygen-related defects such as V n O m complexes [9][10][11][12][13][14][15], and carbon-related defects such C i , C i O i , C i C s , C i Si I , C i O i Si I , and C i C s Si I complexes [16][17][18][19][20][21][22][23][24][25], where V stands for the vacancy, SiI for the self-interstitial, C i for the C interstitial, O i for the oxygen interstitial, and C s for the C substitutional. Most are electrically active, affecting the electrical properties of the material mainly in a negative way.…”