Focused boron ion beam implantation into silicon (original) (raw)
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High Dose Rate Effect of Focused-Ion-Beam Boron Implantation into Silicon
Japanese Journal of Applied Physics, 1984
The effect of high-dose-rate, 16 keV focused-ion-beam (FIB) B+ implantation into Si has been investigated as a function of current density and beam-scan speed. It is shown by µ-RHEED (micro-probe reflection high-energy electron diffraction) observation that the increase in electrical activation of implanted B atoms at such low temperature annealing as 600°C closely correlated with the increase in amorphous zones produced. It is also found that continuous amorphous layer formation occurs with a 1–2×1015 ions/cm2 (one order lower than for conventional implantation) when both implantation conditions of high current density and slow scan speed (e.g. 20 mA/cm2 and 6×10-3 cm/s) are satisfied. The reason for amorphous zone formation enhancement by FIB implantation is discussed.
Ultra low energy (100-2000 eV) boron implantation into crystalline and silicon-preamorphized silicon
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1991
Very low energy (<1 keV) B + ion implantation has been carried out on both crystalline and silicon-preamorphized silicon. The amorphous layer depth was determined using Rutherford backscattering analysis (RBS). The penetration depth and channelling tail of B + ions into silicon was studied as a function of ion energy (100-2000 eV) and low temperature regrowth/annealing (T < 600° C), using secondary ion mass spectroscopy (SIMS). These studies also involved low energy (40-60 eV) ion beam deposition (IBD) of 10-20 nm isotopic 28Si + cap layer at room temperature to enable accurate SIMS depth profile measurements to be carried out. The results show the extent of the channelling tails at these low energies and indicate that sub 40 nm p +-n junctions with estimated carrier concentrations as high as 10 20 cm -3 can be obtained.
Electron - beam annealing of B-, P-, As-, Sb-, and Ga-implanted silicon by multiple-scan method
IEE Proceedings I Solid State and Electron Devices, 1982
Data are presented on the sheet resistance of ion-implanted silicon following isothermal electronbeam annealing by the multiple-scan method. Anneals were performed on implanted 5 mm square chips for times around 5 s, with anneal temperatures up to 1350°C. Implants of As, P, B, Sb and Ga were annealed, ranging in doses from 10 13 cm" 2 to 10 16 cm" 2 in both (100) and (111) orientation silicon, and the sheet resistance was measured with a four-point probe. The measurements are presented as a plot of sheet resistance against electron-beam power, for a given dopant and anneal time, and the corresponding temperatures are also shown. Above a threshold temperature region of 750°C to 950°C near-full electrical activation is obtained, except in cases where the doping level approaches the solid solubility limit, or for certain high-dose boron implants. Slightly lower sheet resistances are obtained for implants in (100) material than (111) material, and at temperatures exceeding 1100°C diffusion effects are expected to be significant. The activation of ion implants without significant redistribution of dopant during annealing can be used to improve the performance of ion-implanted devices.
Lattice location of boron implanted silicon after laser annealing
Lettere Al Nuovo Cimento, 1978
Boron implanted (100)Si specimens were irradiated with Q-swicthed ruby laser pulse of (40+50) ns duration and of 0.7 or 2.7 J/cm 2 energy. The ion implanted amorphous layer becomes single crystal as measured by channeling effect with 1.6 MeV He + baekscattering after 2.7 J/cm ~ laser pulse irradiation, and the boron atoms are almost substitutionally located as determined by the liB(p, ~)SBe nuclear reaction. The 0.7 J/cm 2 laser pulse does not induce the amorphous to single-crystal transition no lattice location of boron was found by channeling, and the implanted ion concentration profile is the same as the as implanted one. Changes in the profile were found instead after the 2.7 J/cm 2 laser pulse irradiation.
Channeling implants of boron in silicon
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1991
80 keV B+ ions were implanted in (100) Si with a high-current implanter. The wafers were irradiated at O" and 7O. The feasibility of the 0 D implants was checked testing the influence of several geometrical parameters, such as the twist angle and the flex angle, on the shape and uniformity of the ion depth distributions. The damage generated by a high-fluence B+ implant was lower for the O" implanted samples and the disorder evolution was analyzed after different annealing processes were performed in the 600-1200' C temperature range. Agglomeration and dissolution of extended defects in the 0" implanted samples occurs at temperatures 100 o C lower than those in the 7 o implanted samples.
Dynamic disordering process in Si during high dose rate B+ ion beam implantation
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1988
The dynamic disordering process in Si during high dose rate focused Bf ion beam (beam diameter 1-2 pm, current density-0.4 A/cm*) implantation has been investigated by cross-sectional TEM observations and ellipsometric analyses. The duration of the scanning ion beam was controlled by changing the beam scan speed. The amount of crystal damage exhibited a strong duration dependence, and more than a one order of magnitude loweimg of the critical dose to form a continuous amorphous layer is observed, compared with that for conventional impl~tation conditions. An activation energy of 0.1-0.2 eV was estimated by the relations between the damage and substrate temperature of the wafer during implantation. This value almost coincides with the migration energy of the doubly negative vacancy (V2-). This result suggests that the migration of V2-plays an important role in the dynamical overlapping of ion damage tracks during high dose rate implantation.
Advanced Ion Implantation Technology for High Performance Transistors
MRS Proceedings, 2001
ABSTRACTCryo-implantation technology is proposed for reducing crystal defects in Si substrates. The substrate temperature was controlled to be below at -160°C during ion implantation. No dislocation was observed in the implanted layer after rapid thermal annealing. Pn junction leakage was successfully reduced by one order of magnitude as compared with room temperature implantation. Precise dose control is indispensable in channel region of high performance MOSFETs. In order to improve the precision of implanted dose, chip size implantation technology without photoresist mask was developed. In this technology, chip-by-chip implantation can be carried out by step-and-repeat wafer stage, and different implantation conditions are available in the same wafer independent of wafer size.
Annealing Effect on Boron High-Energy-Ion-Implantation-Induced Defects in Si
Japanese Journal of Applied Physics, 2004
In this work, we investigate the annealing effect on defects in Si induced by boron high-energy (1.5 MeV) ion implantation with respect to implantation dose (1:1 Â 10 13 and 5 Â 10 13 cm À2) as well as annealing scheme [rapid thermal annealing (RTA) and furnace annealing (FA)]. The higher dose implantation resulted in more serious degradation of the minority carrier generation lifetime in the implanted layers. Also, the degree of lifetime recovery by either RTA or FA was very limited with the higher dose implantation, presumably due to the presence of the implantation-induced dislocations. The degradation of the lifetime in the lower dose-implanted sample could be significantly recovered by the annealing process, particularly the RTA scheme; this is presumably because RTA has a better ability to reduce the implantation-induced interstitials.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1987
The trend towards lower energy implants to form the shallow junctions required by VLSI packing densities has revealed channeling effects that compromise the uniformity of process results. Furthermore, the use of zero degree implants to overcome mask shadowing effects can also result in unacceptable variations in process uniformity from channeling. This paper will provide results which demonstrate that amorphizing self-implants of silicon can be effectively'employed to eliminate these channeling-induced uniformity problems in low energy implants of B ÷. Materials characterization data will be presented to demonstrate the elimination of channeling tails in the implant profile, to reveal the dopant activation characteristics, and to demonstrate that acceptable crystalline recovery can be achieved by annealing which is compatible with present processes.
Range and damage distributions in ultra-low energy boron implantation into silicon
Journal of Stroke & Cerebrovascular Diseases, 1996
An ultra high vacuum, low energy ion implanter was used in conjunction with a range of analytical techniques to study the range and damage distributions of B+ ions implanted at normal incidence into Si(100) samples held at room temperature. Samples were implanted over a dose range from 1E14 ions/cm2 with and without a surface oxide layer and those implanted at 1 keV and below were capped with a nominal 20 nm layer of 28Si by ion beam deposition in situ in order to produce an oxygen equilibration layer for subsequent secondary ion mass spectrometry depth profiling. The samples were analysed using secondary ion mass spectroscopy, medium energy ion scattering, spectroscopic ellipsometry, spreading resistance profiling and high resolution, cross section transmission electron microscopy to obtain the range and damage distributions and junction depths. The general observations were that channelling occurs at all energies studied, and that the relationship between the damage and range distributions depends strongly on bombardment energy. Comparison of the range and damage profiles was carried out to ascertain the role of the surface in determining the behaviour of defects produced very close to it by the low energy implants required for the production of junctions at depths in the 20 to 50 nm range. The role of the surface or silicon/silicon dioxide interface as a defect sink significantly influences the B redistribution behaviour during rapid thermal annealing