Defect Formation of Nickel-Incorporated Large-Diameter Czochralski-Grown Silicon and Their Effect on Gate Oxide Reliability

Abstract

Nickel, the related defect distribution of as-grown nickel-incorporated p-type Czochralski-grown silicon crystals, and its effect on the gate oxide reliability were investigated with respect to the boron doping concentration. The segregation of nickel at the surface was more likely in the doping range of 5.5–7.4 × 1014 cm−3 than in the doping range of 1.1–1.7 × 1015 cm−3, which was due to the active formation of Ni–B pairs in the crystal with a higher boron doping concentration. The formation of surface defects was affected by the atomic nickel distribution; that is, the surface defect density was relatively high in the crystal with a lower boron doping concentration. The gate-oxide reliability was aggravated by nickel-related defects, but this effect was noticeably suppressed in the crystal with a higher boron doping concentration. From the breakdown yield and measured laser scattering tomographic defect density, we found the “transferred portion” of bulk nickel defects that causes a degradation in the gate-oxide reliability.