3 research outputs found
Ion-Beam-Induced Defects in CMOS Technology: Methods of Study
Ion implantation is a nonequilibrium doping technique, which introduces impurity atoms into a solid regardless of thermodynamic considerations. The formation of metastable alloys above the solubility limit, minimized contribution of lateral diffusion processes in device fabrication, and possibility to reach high concentrations of doping impurities can be considered as distinct advantages of ion implantation. Due to excellent controllability, uniformity, and the dose insensitive relative accuracy ion implantation has grown to be the principal doping technology used in the manufacturing of integrated circuits. Originally developed from particle accelerator technology, ion implanters operate in the energy range from tens eV to several MeV (corresponding to a few nms to several microns in depth range). Ion implantation introduces point defects in solids. Very minute concentrations of defects and impurities in semiconductors drastically alter their electrical and optical properties. This chapter presents methods of defect spectroscopy to study the defect origin and characterize the defect density of states in thin film and semiconductor interfaces. The methods considered are positron annihilation spectroscopy, electron spin resonance, and approaches for electrical characterization of semiconductor devices
Electrical properties of Bi-implanted amorphous chalcogenide films
The impact of Bi implantation on the conductivity and the thermopower of
GeTe, Ge-Sb-Te, and Ga- La-S films is investigated. The enhanced conductivity
appears to be notably sensitive to a dose of an implant. Incorporation of Bi in
amorphous chalcogenide films at doses up to 1x1015 cm-2 is seen not to change
the majority carrier type and activation energy for the conduction process.
Higher implantation doses may reverse the majority carrier type in the studied
films. Electron conductivity was observed in GeTe films implanted with Bi at a
dose of 2x1016 cm-2. These studies indicate that native coordination defects
present in amorphous chalcogenide semiconductors can be deactivated by means of
ion implantation. A substantial density of implantation-induced traps in the
studied films and their interfaces with silicon is inferred from analysis of
the space-charge limited current and capacitance-voltage characteristics taken
on Au/amorphous chalcogenide/Si structures.Comment: arXiv admin note: substantial text overlap with arXiv:1410.567
Electrical properties of Bi-implanted amorphous chalcogenide films
The impact of Bi implantation on the conductivity and the thermopower of
amorphous chalcogenide films is investigated. Incorporation of Bi in Ge-Sb-Te
and GeTe results in enhanced conductivity. The negative Seebeck coefficient
confirms onset of the electron conductivity in GeTe implanted with Bi at a dose
of 2x1016 cm-2. The enhanced conductivity is accompanied by defect accumulation
in the films upon implantation as is inferred by using analysis of the
space-charge limited current. The results indicate that native coordination
defects in lone-pair semiconductors can be deactivated by means of ion
implantation, and higher conductivity of the films stems from additional
electrically active defects created by implantation of bismuth.Comment: This is an extended version of the results presented in Proc. SPIE
8982, 898213 (2014