Amorphization by ion implantation has been investigated in films of (SmYGdTm)3Ga0.4Fe4.6O12 garnet by transmission electron microscopy, incorporating a special cross-sectioning technique. These films were produced by liquid phase epitaxy on (111) garnet substrates and subsequently implanted with ions of deuterium at 60 keV and doses ranging from 0.50 to 4.5×1016 D2+/cm2 and ions of oxygen at 110 keV and doses ranging from 0.95 to 8.6×1014O+/cm2. The amorphization process proceeds in separate stages involving the formation of isolated amorphous regions, merging of these regions into a continuous band and subsequent propagation of the amorphous band toward the implanted surface. Details of these processes are interpreted in terms of various atomic displacement mechanisms.

Ion implantation induced phase transformations and recrystallization during post-annealing in CoSi2, CrSi2, and Pd2Si are studied. All three silicides are found to reorder at about 1/3 the melting point of the silicide. We speculate that ion-implanted silicides recrystallize by the same mechanism and that amorphous phases produced by implantation are unstable rather than metastable.

The microstructure of aluminum annealed after implantation to peak concentrations of approximately 4.4 and 11 at. % Mo was investigated by analytical electron microscopy. Al12Mo precipitates formed with pseudo-lamellar and continuous film microstructures. Video recordings of insitu annealing experiments revealed the details of the phase transformations.

The results of transmission electron microscopy studies of iron implantation into high purity aluminum foils are described. For both 50 and 100 + 50 keV incident ion energies, modulated structure has been detected in the as-implanted foils. Upon annealing at 793 K the modulated structure decomposes into the Al matrix and Al3Fe precipitates for the 50 keV implantation. A similar annealing treatment for the 100 + 50 keV implantation indicates that the modulated structure is more stable, although some Fe3Al precipitation occurs.

A supralinear dose dependence for the amorphous transformation was observed in NiTi during bombardment with 2.5 MeV Ni+ ions. These results are consistent with a mechanism that requires cascade overlap to obtain a critical defect density for the amorphous transformation. Direct amorphization in the cascades was not resolvable. The temperature dependence of the minimum dose required for complete amorphous transformation had the same form as that observed for amorphization of silicon. Amorphization caused by electron bombardment required a higher dose than by ion bombardment. Different degrees of homogeneity of the damage state between ions and electrons can explain the dose dependence on particle type.

Pure, polycrystalline nickel samples were implanted with lithium to doses up to 5 × 1017 lithium ions per square centimeter, at a temperature of 500°C, such that the implantation damage would anneal. These samples were then prepared for electron microscopy and examined at 1 MeV, in the Argonne National Laboratory HVEM facility. It was observed that compared to pure nickel, the lithium implanted nickel showed a different radiation damage behaviour. A plausible explanation for the difference in behaviour is presented in this paper.

The lithium implanted nickel, in the high dose samples, also showed an unusual form of precipitation. Electron microscopy revealed the precipitates to have truncated octahedral shapes with {111} planes for sides and {100} planes truncating the corners. They resemble voids and helium bubbles in nickel. The precipitates appear to be associated with dislocations. The lithium implanted nickel was internally oxidized in order to obtain evidence for the presence of lithium. Electron diffraction analysis of the internally oxidized lithiated nickel showed the presence of a topo-taxial compound being formed, with an ordered NaCl-structure. Possible interpretations of this diffraction pattern are discussed.

Ion mixing of FeNi-Si multilayers is performed at the same dose of 3.1015 Xe+ cm−2 with either of the three energies 200, 300 or 400 keV. The irradiation is done at liquid nitrogen temperature (LNT) or at room temperature (RT). The mixed layers are characterized by reflection high energy electron diffraction (RHEED), transmission electron microscopy (TEM), Rutherford backscattering (RBS), secondary ion mass spectroscopy (SIMS) and ferromagnetic resonance (FMR). Films made at 400 keV are more reproducible and as homogeneous as the best amorphous films realized up to now, using sputtering techniques.

High-purity, polycrystalline foils of 12 atomic percent gold Ag-Au alloy were implanted with polyatomic ions of arsenic and antimony at energies of 45 keV per atom. During fluence intervals before and after the steady state, sputtered material was collected on high-purity strips of aluminum foil. Subsequent backscattering analysis of the targets and collectors showed that significant redistribution and segregation occurred in the implanted layer, with relative depletion of silver consistently observed. The results suggested that preferentiality in sputtering is dependent on composition of an alloy and the ion beam used (even at low fluence), but there appears to be no major difference between the redistribution behavior of targets sputtered with atomic ions and equal-velocity molecular ions.

A model is presented which predicts the sputtering behavior and surface configuration of a binary alloy implanted to steady state with a third species.

Low and high dose hafnium imolanted beryllium samoles have been prepared at room temperature by ion implantation of beryllium commercial foils and single crystals. These samples have been studied before and after annealing with the time differential perturbed angular correlation method (TDPAC) and with Rutherford backscattering and channeling techniques. A new metastable system has been discovered in TDPAC-measurements in a low dose hafnium implanted beryllium foil annealed at 500°C. Channeling measurements show that the hafnium atoms after annealing, are in the regular tetrahedral sites but dislocated from the previous position occupied after implantation. The formation of this system is connected with the redistribution of oxygen in a thin layer under the surface. This effect does not take place precisely at the same temperature in foils and in single crystals.

The characteristics of an anomalous morphological instability initiated in amorphous Ge by heavy ion bombardment are reviewed and a model based on defect-production/defect-interactions is proposed.

This paper presents new data on the previously observed porous structures which can be developed in high dose, ion implanted Ge. In addition, we provide strong evidence to suggest that such porous structures can be formed in high dose, ion implanted Si and GaAs substrates under particular implant conditions. Comparison of the various systems using RBS analysis indicates that heavy ion doses as low as 1014 cm−2 can give rise to such structural modifications in GaAs, whereas doses of 1015 cm−2 are needed to observe an effect with Ge and doses usually exceeding 1016cm−2 are required for Si.

Amorphous Si and Ge layers, produced by noble gas (Ar or Xe) implantation of single crystal substrates, have been crystallized in a differential scanning calorimeter (DSC). This technique allows determination of the growth velocity (which is proportional to the rate of heat evolution, ΔHac), and the total enthalpy of crystallization ΔHacAmorphous Ge was found to relax continuously to an amorphous state of lower free energy, with a total enthalpy of relaxation of 6.0 kJ.mole−1 before crystallization started. The regrowth velocity on (100) substrates,measured to be 4.2×1017 exp (−2.17eV/kT)Å/sec, is compared to other determinations. The value of ΔHac was found to be 11.66± 0.7 kJ.mole, in good agreement with ΔHac for amorphous Ge produced by other methods. For Si, ΔHac was determined to be 11.95± 0.7 kJ.mole without any evidence of heat release due to relaxation. The kinetics of crystallization measured by DSC are compared with those determined by other techniques. The effects of the implant profile on the regrowth velocity could also be observed directly in the DSC signal. The more accurate value of ΔHac allowed a more precise determination of the melting temperature of amorphous Si: Taℓ= 1420K.

Characterization of the two metastable states of amorphous Si produced by ion implantation is extended to include electron paramagnetic resonance, fundamental absorption edge, and density measurements in addition to infrared reflection. It is found that the properties of the two a-Si states are not dependent upon the mass of the incident ion (12C, 29Si, 31p, 120Sn) or upon the anneal temperature for 400°≤TA≤600°C. The dangling-bond density drops about a factor of 2, the absorption coefficient drops by more than a factor of 5, but the density does not change when the a-Si makes a transition between the two states.

Heavy rare gases implantations have been performed in layered structures : Sb/In/Si bulk and Sb/Ga/Si bulk. Layer thicknesses lie in the range of 150 Å – 600 Å, ion doses in the range of 1014 cm−2 – 1016cm−2

Ion implantation induces in such structures a change in the visual aspect from a metallic appearance to a dark black aspect. This modification corresponds to the creation of voids with, as a consequence, the expansion of the structure. This effect is so important that even for low and medium doses, the structure becomes filamentary. Expansions as high as 2,8 μm have been measured. SEM photographs illustrate this spectacular effect.

Relations between expansion and implantation parameters are given. A comparison between this effect and those observed in bulk InSb, GaSb and Ge is presented.

This paper outlines a model to account for the influence of doping and electronic processes on the solid phase epitaxial regrowth rate of ion implanted (100) silicon. In addition we present data which illustrates good quality epitaxial crystallisation of silicon at 400°C induced by He+ ion irradiation. We tentatively suggest that electronic energy-loss processes may be responsible for this behaviour.

Annealing of amorphous layers in Si by high flux, selfion irradiation will be discussed. The mechanism for the lattice recovery is presented and related to the structure of the residual damage. It will be shown that highly supersaturated, alloyed regions, free from extended defects, result from the annealing process.

Substrates can undergo major temperature excursions during ion implantation if they are not well heat sunk. At power densities on the order of 50 watts per cm−2 radiatively cooled Si will melt in a matter of seconds. Such power densities can be maintained over a few sq. cms with many of the beams produced by even the moderate current machines currently used for doping Si and the III-V's. We have made use of this fact to study pulsed ion-beam annealing of implanted Si. Two types of studies have been carried out. In the first, 5–20 sec proton irradiations were done at power densities of 3–35 watts cm−2 to produce sample temperatures of 500 to 1100°C. 2×1016 cm−2 280 keV B, BF2 , As and P implants were annealed in this manner. Sheet resistances, ρs, versus power density curves were obtained for each ion and compared to psρs vs T data obtained for furnace annealed companion samples. In the second study the 2×1016cm−2 280 keV implants were carried out at progressively higher current densities so that the dopant beam itself raised the sample temperature to 500–1000°C. For each ion (other than B) it was possible to obtain power densities which resulted in self-annealing implants whose sheet resistances were as low as those obtained with the optimal furnace anneal. Details of the experiments, electrical and physical properties of the pulsed ion-beam annealed layers and device applications will be presented in this paper.

We have employed high resolution ion channeling and TEM methods to investigate the damage production and dynamic annealing processes which take place in (100) silicon bombarded at elevated temperatures. Two important observations have arisen from our results i) We have observed an amorphisation process for Sb-implanted silicon at 250°C which is more akin to amorphisation processes in metals, whereby the impurity (Sb) appears to influence the stability of amorphous zones associated with individual ion tracks. ii) We have demonstrated that previously amorphised layers in silicon can be recrystallised through a solid phase epitaxial process by subsequent bombardment with He+, Ar+ and Sb+ ions at substrate temperatures of 300–400°C, which are significantly below normal thermal regrowth temperatures of >500°C.

Formation of buried p-type and n-type layers in (100) silicon has been accomplished by implanting with 4 MeV boron and 11 MeV arsenic ions respectively. The projected range (Rp) of 4 MeV boron is 5.2 microns with a straggle (ΔRp) of .2 microns. The 11 MeV arsenic implant has a Rp of 4.37 microns with a ΔRp of .37 microns. The 4 MeV boron implant was carried out to a dose of l×1015/ cm2 while the 11 MeV arsenic implant dose was 1.9×1015/ cm2. For both dopants the target holder could be cooled with either liquid nitrogen (LN) or flowing room temperature water (RT). Buried amorphous regions are seen by cross sectional transmission electron microscopy (XTEM) for both boron and arsenic when LN cooling is used. Arsenic shows a buried amorphous region for the RT case as well. The extent of the buried amorphous regions are compared with the energy deposited into nuclear stopping as determined by computer simulation. Threshold levels are determined for the creation of these buried amorphous regions. The boron samples were annealed for 30 minutes at 900°C in a nitrogen ambient, and XTEM shows no residual damage for both cooling conditions. The arsenic samples underwent a two step annealing procedure; 545°C for 16 hours followed by a 945°C step for 15 minutes. Regions containing dislocation networks are observed by XTEM for both cooling conditions.

The 4 MeV implanted boron buried layer was applied to an NMOS process. Transistors fabricated above the p-type buried layer show channel mobility, threshold voltage, and sub-threshold leakage which are indistinguishable from transistors fabricated without the buried layer. Vertical npn bipolar transistors have been fabricated using the 11 MeV arsenic buried layer to form the collector. Electrical characteristics from both these devices indicate that megavolt ion implantation can be applied to silicon for active device geometries.

Chlorine- and iodine-implanted silicon have been investigated using the channeling/RBS technique after laser and oven annealing. Both annealing methods result in good epitaxial recrystallization of the implanted layer. A large near-substitutional I fraction exceeding 90% was found after oven annealing at 875°C. The near-substitutional fractions found after laser annealing for Cl and I, and after thermal annealing at 900°C for Cl are in the order of 50% only. The precise lattice site for these Cl and I fractions are determined by fitting the angular scans with simulated results. The results are interpreted in terms of vacancy association.