Ultralow energy boron implants in silicon characterization by nonoxidizing secondary ion mass spectrometry analysis and soft x-ray grazing incidence x-ray fluorescence techniques

Abstract

Grazing incidence x-ray fluorescence and secondary ion mass spectrometry combined approach for the characterization of ultrashallow arsenic distribution in silicon Secondary ion mass spectrometry characterization of the diffusion properties of 17 elements implanted into silicon J.Approach to the characterization of through-oxide boron implantation by secondary ion mass spectrometry Study of pre-equilibrium sputter rates for ultrashallow depth profiling with secondary ion mass spectrometry Boron ultralow energy ͑0.2-3 keV͒ high dose ͑1 ϫ 10 15 cm −2 ͒ implants in single crystalline Si ͑100͒ were characterized by secondary ion mass spectrometry using an ultralow energy ͑0.35-0.5 keV͒ O 2 + ion primary beam and collecting positive secondary ions. In particular, the not fully oxidizing approaches ͑primary beam oblique incidence and ultrahigh vacuum analysis atmosphere͒ were investigated because they are expected to provide better accuracy on the profile shape, especially in the region between the surface and the native oxide/substrate interface. The main drawback represented by an early formation of roughness on the crater bottom has been overcome by combining the ion sputtering with the rotation of the sample during the analysis. The reduced formation of roughness ensures more stable sputtering conditions and a more stable erosion rate with a more accurate depth calibration. The measured dose values were then cross-checked comparing them with results of soft x-ray synchrotron radiation grazing incidence x-ray fluorescence.

Depth profiling of low energy ion implantations in Si and Ge by means of micro-focused grazing emission X-ray fluorescence and grazing incidence X-ray fluorescence

“…The tunability of the probed depth region with the grazing angle in combination with the linearity in the intensity response of X-ray detectors was already applied to depth-proling measurements of ion-implanted samples (Al, As and B dopants in Si wafers were considered) by means of GEXRF and GIXRF. [46][47][48][49][50][51] It has to be pointed out that for the reported dopant-wafer combinations, the measurements could be performed either with excitation energies below the Si K-edge (1839 eV), thus avoiding a signicant background contribution from the wafer material or at energies above the As K-edge (11867 eV). In the latter situation the Si absorption cross-section is small and the As XRF signal can be well separated from the Si Ka line.…”

Development of nano‐roughness under SIMS ion sputtering of germanium surfaces

“…On the other hand, in the case of rotation, the surface roughness remain nearly stable and comparable with the roughness of the initial surface. It should be noted that roughness evolution of germanium surfaces after low energy ion sputtering is less pronounced than the one observed in Si for similar ion dose exposures . In particular, S q on germanium remain below or around 1 nm even after a 400‐nm erosion, and thus the impact on depth resolution deterioration should be very limited.…”

“…SIMS analysis was performed in both ultra‐high vacuum (~10 −9 mbar) and using an oxygen leak (~10 −6 mbar, not used for Cs + bombardment). A Zalar rotation was applied in order to reduce the formation of ripples, i.e. sample was rotated around the surface normal axis during ion bombardment (12 revolutions per minute).…”

Development of nanotopography during SIMS characterization of thin films of Ge1−Sn alloy

“…For low ion fluence (up to ∼7 × 10 15 cm −2 ) only disordered dot arrays were observed in both configurations. This is expected for Zalar rotation craters, as observed in Si at similar incidence angle [23] whereas it is somehow surprising for craters without rotation, where oblique incidence usually implies the formation of ordered "ripples". In fact, it is known that in semiconductor material, low-energy ion beam sputtering can produce topography: depending on the range of irradiated fluence [8] and on incidence angle of ion beam [7], dot arrays form for normal incidence [24], whereas ripples for offnormal ion beam [6][7][8].…”