Ion implantation damage recovery in GaN

We present a method of ion implantation doping of GaN, which permits reduced residual damage. The method consists of performing implantation in several steps with annealing between each step. Residual damage was analyzed by RBS/channeling and compared to a traditional implantation and annealing procedure. Better lattice recovery is clearly achieved using the alternating implantation and annealing approach. We attribute the efficient recovery to smaller damage amounts introduced during each implantation step, as well as to suppression of secondary defect formation.     

Structural changes of Si surfaces by nitrogen implantation using plasma based ion implantation

Nitrogen ion implantation to Si wafers is carried out by a plasma based ion implantation (PBII) and the compositional and structural changes of the Si surfaces are examined as a function of implantation time by energy dispersive X-ray spectrometer (EDX), Raman and Fourier Transform Infrared (FT-IR) spectroscopy. The implantation time is varied from 10 min to 7 h. From the results of EDX measurements, the N concentration is increased with increasing implantation time up to 1 h, but it is not significantly increased at further increase of implantation time. In the Raman spectra, the sharp peak from Si crystal is decreased in intensity and the small peaks from a-Si and/or a-SiN_x appear after N ion implantation. On the other hand, in the FT-IR spectra, a broad peak assigned to Si–N bonds appears after N ion implantation. The result of RBS measurement indicates that the N/Si ratio is approximately 1.3. Judging from these results, it is suggested that a-SiN_1.3 is formed as a surface layer on Si wafer by N ion implantation using PBII system.     

EPR study of defects produced by MeV Ag ion implantation into silicon

The damage produced by implanting (1 1 1) Si wafers with 4 MeV Ag ions at implantation temperatures of 210, 350 and 400 K has been investigated by electron paramagnetic resonance as a function of implantation fluence in the range 5 × 10¹²–2 × 10¹⁵ Ag cm⁻². For each implantation temperature, at low ion fluences the EPR spectra show the presence of the point defect centres Si-P3 (neutral 4-vacancy) and Si-P6 (di-interstitial) as well the so-called Σ defect complexes. As the implantation fluence is raised the population of P3 centres goes through a maximum while the Σ centre resonance is gradually replaced by the spectrum of the well-known Si-D centre of a-Si. For implantation at 210 K the total Σ+D centre concentration increases linearly with implantation fluence up to the point at which an amorphous layer is formed; however raising the implantation temperature causes the dependence of the Σ+D concentration on implantation fluence to become increasingly sublinear with the result that the production of a given level of damage requires a larger implantation fluence. The results are discussed in the context of a previous study of the implantation damage in the same samples by optical reflectivity depth profiling [Mat. Res. Soc. Symp. Proc. 540 (1999) 31].     

Experimental Study on Material Surface Modification of Tool Steel

This paper presents the surface temperature behavior of M42 high-speed tool steel samples during N^ implantation in an industrialized GLZ-100 metal-ion implantation machine.A detail study has been made on the parameters of N^ implantation.Optimized technical parameters have been preseted.The microhardness of the sample surface implanted under these parameters has been increased by a factor of 2.3.and the wear-resistance has been improved by about 5.4 times.The research on the mechanism of surface modification of M42 steel by nitrogen ion implantation has also been made.     

Etude par microscopie electronique d'un alliage aluminium-cuivre a 1.3% atomique obtenu par implantation

An Al-Cu alloy of 1.3 at% is obtained by implantation of Cu ions in thin foils of aluminium. The purpose of the electron-microscope study is to determine the ageing reactions of this alloy as compared with those occuring in the quenched solid solution.It has been shown that the implantation temperature is an essential parameter in the unmixing process. After a 77 K implantation 8 months of ageing at 20°C are necessary to obtain the first stages of unmixing characterized by the formation of Guinier-Prestion I zones (GP(I) zones), whereas after an implantation at room-temperature, the θ″ phase is directly observed. The behaviour of the solid solution obtained at 77 K is similar to the conventional Al-Cu solid solution. On the contrary, during the implantation at room-temperature, the unmixing is already started and this fact can be explained on account of an enhanced diffusion.     

离子注入在刀具上应用的研究

能量为几十千到几百千电子伏离子射入材料表面,使表面层的组成与结构发生改变,从而引起材料表面的物理与化学性质的变化,这种材料改性方法有极其重要的应用。如摩擦、润滑性、耐磨损性、表面硬化、抗高温氧化性、耐腐蚀性、催化及附着力改善等。虽然离子注入可改善材料这些性质,但由于经济与技术上的原因,最重要的研究集中在耐磨损性、抗高温氧化性及某些耐蚀性上,而耐磨性的研究以工具上的应用为最多。     

Annealing Studies of Damage Introduced by High Energy Ion Implantations of Silicon

Ion implantation of dopant impurities into semiconductors offers numerous potential advantages. However, because of the limited knowledge presently available on the annealing of lattice damage, the implantation profile and the electrical characteristics of implanted layers, a considerable amount of investigation is required before this doping technique can be put to practical use. Experimentally obtained implantation profiles and electrical conductivity characteristics of high energy (above 1 Mev) dopant ion implants into silicon are presented. Some preliminary results of ion implantation on silicon dioxide and on the resulting devices are also included.     

Defects in carbon and oxygen implanted p-type silicon

Both oxygen and carbon ion implantation are frequently used to form either insulating buried SiO₂ or SiC layer for various purposes. This creates a renewal of the interest in defects produced during such implantation processes. In the present paper we report on deep level transient spectroscopy studies of defect states occurring in boron-doped p-type silicon after high dose C⁺ and CO⁺ ion implantation and subsequent thermal annealing. It is shown that the predominant defect created during the implantation is in both cases related to silicon selfinterstitial clusters, which upon annealing at higher temperatures evolve to extended structural defects.     

Effects of Ion Implantation on in Vitro Pollen Germination and Cellular Organization of Pollen Tube in Pinus thunbergii Parl. （Japanese Black Pine）

Low-energy ion implantation, as a new technology to produce mutation in plant breeding, has been widely applied in agriculture in China. But so far there is a little understanding of the underlying mechanisms responsible for its biological effects at the cellular level. Here we report the biological effects of a nitrogen ion beams of 30 keV on the pollen grains of Pinus thunbergii Parl. In general, ion implantation inhibited pollen germination. The dose-response curve presented a particular saddle-like pattern. Ion implantation also changed the dimension of the elongated tubes and significantly induced tip swelling. Confocal microscopy indicated that the pollen tube tips in P. thunbergii contained an enriched network of microtubules. Ion implantation led to the disruption of microtubules especially in swollen tips. Treatment with colchicine demonstrated that tip swelling was caused by the disruption of microtubules in the tip, indicating a unique role for microtubules in maintaining the tip integrality of the pollen tube in conifer. Our results suggest that ion implantation induce the disruption of microtubule organization in pollen and pollen tubes and subsequently cause morphological abnormalities in the pollen tubes. This study may provide a clue for further investigation on the interaction between low-energy ion beams and pollen tube growth.     

Lattice damage and secondary phase formation in Yttria stabilised zirconia implanted with Fe at different temperatures

In this paper we report on the lattice damage and nanocrystalline secondary phase formation in Fe implanted Yttria stabilised zirconia (YSZ) up to a peak concentration of 10%. The implantation temperature has been varied between room temperature and 1000 °C. Samples were characterized using Rutherford backscattering/channeling and X-ray diffraction. We observed that (1) YSZ remains partially crystalline even after Fe implantation at room temperature and the lattice damage can be partially recovered if implantation is performed at elevated temperatures; (2) crystalline bcc-Fe nanoparticles have formed and grown with increasing implantation temperature. The nanoscale Fe precipitates and the YSZ matrix have a crystallographic orientation relationship.