[en] The main progress in materials modification by ion beam technology at the Shanghai Institute of Metallurgy is reported. The production of SIMOX and SIMNI by high dose implantation of O⁺ and N⁺ ions, synthesis of TiN, Si3N4, and other hard coatings by ion beam enhanced deposition, epitaxial growth of high Tc superconductive thin films and their damaging behavior under ion beam bombardment, and surface modification of semiconductors, metals and polymers by ion implantation, have been widely investigated. In addition, industrial application trials were carried out. 28 refs., 17 figs

[en] The purpose of this paper is to report some experiments with HfO₂ film, which was deposited onto silicon substrates at different growth rates by electron beam evaporation. The chemical states were measured by X-ray photoelectron spectroscopy (XPS). The rms roughness as low as 0.85 nm was measured by atomic force microscope (AFM). Scanning electron microscopy (SEM) was also used to determine cross-section morphology. Spectroscopic ellipsometry (SE) was applied to measure the refractive index, extinction coefficient and the thickness of the films. The results of SE presented the refractive indices varied in the range of 1.81-1.95 around 1550 nm by altering deposition rates. The transmittance and reflectance spectrum were measured to determine the effectiveness of HfO₂ thin film as a single layer anti-reflection coating on Si substrates. The results suggested that the Fresnel losses below 0.05 dB/chip are achieved by depositing HfO₂ film onto SOI rib waveguide endface

[en] Arsenic ions were implanted into silicon-on-insulator (SOI) structures at an incident energy of 100 keV to a dose of 2 x 10¹⁵ cm^-2. Conductive top layers were formed in the SOI structures after annealing at 1200^oC for 20 s. Infrared reflection spectra in the wave number range of 1500-5000 cm^-1 were measured and interference fringes, related to free-carrier plasma effects, were observed. By detailed theoretical analysis and computer simulation of infrared reflection spectra, the carrier concentration, the carrier mobility, and the carrier activation efficiency were obtained. The physical interpretation of the results and a critical discussion of the sensitivity of the data, fitted to variation in the parameters, are given. (author)

[en] The electrical properties and characteristics of photoluminescence (PL) at 11K for InP implanted with Si⁺ at 200 deg C have studied. It has been found that the sheet electron concentration in Si⁺ simply implanted sample tends to a saturation level with increasing the Si⁺ dose, while that in Si⁺ + P⁺ dually implanted sample increases greatly. The 11k PL spectra reveals that there exists Si_P-V_P complex in Si⁺ implanted InP, which can be inhibited by co-implanting P⁺. The mechanism of improved electrical properties by Si⁺ + P⁺ dual implants is also discussed

[en] Si⁺ was implanted into top silicon of SOI (silicon on insulator) material formed by N⁺ implantation to amorphize its surface, interface area between the top and the buried layer, and the whole top silicon. Then these SOI wafers and those without implantation were implanted by B⁺ at 25 keV with dose of 1 x 10¹⁵/cm² and annealed in dry N₂ ambient at different temperatures in the range of 500 C deg to 900 C deg for 30 min. Glancing RBS/c measurement has shown that a solid phase epitaxial regrowth from the inner part of top silicon towards the surface or in the opposite direction exists respectively during post annealing if the surface or interface area of top silicon is amorphized. When the whole top silicon is amorphized, there is a phase transition from amorphous silicon to polysilicon for the silicon during post annealing in the temperature range from 500 C deg to 600 C deg, and no solid phase epitaxial regrowth is found when the temperature is increased to 900 C deg. Spreading resistance probe measurements show that the activation rate of implanted boron in the top silicon is lower than that in crystalline bulk silicon. The activation rate of implanted boron in the top silicon can be increased either by using Si⁺ implantation (to amorphize the surface or the interface area of top silicon) or by the solid phase epitaxial regrowth

[en] The possibility of forming carbon nitride CN_x by high dose nitrogen implantation into carbon film has been investigated. The sample is evaluated by Fourier transformation infrared absorption spectroscopy (FRIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction analysis (XRD) and Vickers microhardness measurement. The results verify the formation of C-N covalent bond in the sample during the process of high dose nitrogen implantation into carbon film

[en] A new configuration of carbon nanotubes (CNTs), whose surfaces are fully covered with nanosized node-like structures, has been observed. The node structures have almost the same size (40-50 nm). We named this material nodose carbon nanotubes (NCNTs). Field emission scanning electron microscope shows that common CNTs are changed to NCNTs after hydrogen plasma surface treatment in our homemade plasma equipment. Experiments verified that this material has good field emission characteristics, low threshold field of 1.12 V/μm, emitting current density of 1.72 mA/cm² at a field of 10.4 V/μm and very high emission site density of about 10⁶/cm², which is three orders of magnitude higher than that from common CNT films. These results indicate that the CNTs with nodose structure are a very good field emitter material

[en] Dual implantations of Si⁺ and P⁺ at elevated temperatures were used to study the amphoteric property of Si in InP. The electrical properties from Hall measurements indicate that improved activation is obtained in dually implanted samples, and in-diffusion of Si species is inhibited by implantation of P species. Photoluminescence spectra at 11 K proved that the implantation of P species can suppress the formation of deep Si acceptors formed from substantial Si at P sites effectively. All these results demonstrate that as in GaAs, Si is an amphoteric dopant in InP and that high carrier concentration can be attained by dual implantations. (author)

[en] As the second part of our program, an attempt has been made to investigate the effect of N⁺ ion beam bombardment on the aqueous corrosion behaviour of Fe/Cr and Fe/Al systems by means of electrochemical and electron-optical techniques. Fe deposited with Cr (400 A) and Al (800 A) were bombarded by a N⁺ ion beam with an energy of 150 keV at a dose of 5x10¹⁶ N⁺/cm. The anodic current Isub(c) and Isub(m), as displayed on anodic polarization curves for both Fe/Cr and Fe/Al systems, were decreased by one order of magnitude. It is mainly related with the chemical effect of N⁺ ion implantation, and presumably associated with formation of a metastable phase of nitride as a barrier layer reducing the anodic dissolution. (orig.)

[en] N-type <100> crystalline silicon wafers were implanted by N⁺ at 170 keV with doses ranging from (0.5-2.2)x10¹⁸/cm². All these implanted wafers were annealed at 1200degC for 2 h in dry-N₂ ambient. Infrared (IR) transmission spectroscopic measurements showed that a buried α-Si₃N₄ layer was formed for those wafers in which the dose of implanted N⁺ was higher than 1x10¹⁸/cm². B⁺, Si⁺ and Ar⁺ were implanted into these wafers to amorphize the buried α-Si₃N₄ in order to improve its insulating properties. IR measurements indicated that Si⁺ and Ar⁺ implantations can amorphize the buried α-Si₃N₄. Though the deposited energy density of B⁺ was higher than that of Si⁺ and Ar⁺, buried α-Si₃N₄ cannot be amorphized by B⁺ implantation. These wafers were annealed at 900 and 1150degC for 45 min. Amorphized nitride recrystallized to form α-Si₃N₄ after annealing at 1150degC. Ohmic contacts were fabricated at front and back sides for all wafers by As⁺ implantation and aluminium evaporation. I-V characteristics were measured and the effect of B⁺, Si⁺, and Ar⁺ implantations on insulating properties of the buried insulator was studied for all samples. (orig.)