Deep level centers in electron‐irradiated silicon crystals doped with copper at different temperatures

Abstract

The effect of bombardment with energetic particles on the deep‐level spectrum of copper‐contaminated silicon wafers is studied by space charge spectroscopy methods. The p‐type FZ‐Si wafers were doped with copper in the temperature range of 645–750 °C and then irradiated with the 1015 cm−2 fluence of 5 MeV electrons at room temperature. Only the mobile Cui species and the CuPL centers are detected in significant concentrations in the non‐irradiated Cu‐doped wafers. The properties of the irradiated samples are found to qualitatively depend on the copper in‐diffusion temperature Tdiff. For Tdiff > 700 °C, the irradiation partially reduces the Cui concentration and introduces additional CuPL centers while no standard radiation defects are detected. If Tdiff was below ∼700 °C, the irradiation totally removes the mobile Cui species. Instead, the standard radiation defects and their complexes with copper appear in the deep‐level spectrum. A model for the defects reaction scheme during the irradiation is derived and discussed.DLTS spectrum of the Cu‐contaminated and then irradiated silicon qualitatively depends on the copper in‐diffusion temperature.

Copper Complexes with Carbon‐Related Radiation Defects in Silicon

“…Radiation defects were introduced at room temperature into p‐type Si wafers ([B] 10 15 cm −3 ) containing 310 14 cm −3 mobile species, which corresponds to a high level of copper contamination. [ 10 ] (For the preparation of Cu‐doped wafers and measurements of the concentration, see Section 6.) Accordingly, the irradiation‐induced vacancies were transformed first to and then to the centers.…”

“…Interaction of copper with radiation defects is the subject of several works. [1][2][3][4][5][6][7][8][9][10] Evolution of the vacancy-type defects is understood rather well: The final defect spectrum strongly depends on the copper contamination level. [10] The dominant vacancy-type radiation defect, VO, is transformed into the CuVO complex under the conditions of low copper concentration.…”

“…[ 1–10 ] Evolution of the vacancy‐type defects is understood rather well: The final defect spectrum strongly depends on the copper contamination level. [ 10 ] The dominant vacancy‐type radiation defect, V O, is transformed into the Cu V O complex under the conditions of low copper concentration. [ 6 ] When the concentration is high, the primary vacancies are consumed in the reaction with and the V O and Cu V O complexes are not formed.…”

Location and Properties of Carrier Traps in mc‐Si Solar Cells Subjected to Degradation at Elevated Temperatures

“…of degradation for the samples in all these publications also supports this supposition. Explanation for the observed lateral distribution of the degradation in the case of Cu-LID may be related to the fact that relatively large Cu-precipitates (i.e., visible in SEM) formed close to/at GB are less recombination active in comparison with small Cu complexes (e.g., Cu 3 Si) homogeneously dissolved in the grains and activated by illumination during carrier injection at elevated temperatures (see previous studies [4,64,65] and references therein).…”

Electrical Activation of Interstitial Ni in Cu‐Doped Si

“…[ 4 ] In case of copper, the transformation was demonstrated to proceed at room temperature due to vacancies created by irradiation with energetic particles. [ 5,6 ] In this work, we consider the situation when is introduced at near room temperatures into the crystals, where vacancies were already occupied by copper ().…”