Isotopically enriched iron (56Fe or 57Fe) films were deposited on Si(100) substrates at RT by a low-energy (50–500 eV), mass-separated ion beam deposition (IBD) method. All the IBD-Fe films had smooth and fine-grained polycrystalline bcc-structure, and showed superior electrochemical corrosion resistance against both NaCl and H2SO4 solutions compared with die highest-purity (RRRIH=6000) iron metals ever reported. A distinct energy dependence of the degree of corrosion resistance and different microcrystalline structures observed by TEM cross-sections for the 50 eV- and 100 eV-IBD-Fe films indicate that their film growth modes are completely different.

Ion beam controlled deposition (IBCD) or ion beam assisted deposition (IB AD) of Ti(C,N,O) films has been investigated much in the last decade for both the advantage of this advanced technology and the promising properties of such materials. Ti(C,N,O) films are various solid solutions of interstitial compounds TiC, TiN and TiO of F.C.C structure with lattice constants lying between the values of the pure compounds. Some content of oxygen improves their wear resistance due to the lower fn;e enthalpies of such films in comparison with pure TiC and TiN films [1]. Many so-synthesizcd titanium carbide and titanium nitride films reported in published papers were actually of this sort as they often had more or less oxygen content from residual gas in vacuum. A number of papers were contributed to depict the texture and composition dependence of film on the arrival ratio of assisting ions versus deposited atoms (AR) as well as their mechanical properties [2–6]. However, the film formation mechanism in IBCD isn't quite clear yet, especially for cases with assisting ion energy of several to tens of keV. During a course to synthesize Ti(C,N,O) films by IBCD with the two beam technique, datum were accumulated. Based on a part of it, a previous paper on ion beam governed preferential growth in IBCD has been published [7]. This paper was aimed to search for the origin of ion bombardment effect on film hardness.

An unique method is used to produce a low energy nonthermalized fast neutral radical beam wliich can activate the SiO2 surface for chemical reaction at the desired incident energy. The fast neutral beam energy is continuously adjustable (2eV<Ek<200eV) and the beam flux is typically 5×1015cm−2 sec−1(∼4L). An uniform large diameter plasma is also made for the production of neutral beam covering 5”wafer and larger. Large diameter neutral beam single wafer reactor is feasible with off-the-shelf pumping technology.

Precise control of critical dimension(CD) loss (defined as the length of the top of contact hole minus the bottom of resist in this paper) and etched profile of contact holes is a key technology in the fabrication of Ultra Large Scaled Integrated Circuit(ULSI). In case of fine contact hole etching, small CD loss and vertical profile is essential. We have found out that N2 addition to Ar/CHF3/CF4 sharpens etched profile with CD loss kept small. And N2 addition also increases etch rate without a heavy deterioration of selectivity of SiO2 versus heavily doped n-type poly cry stall ine Si(n+ poly Si). Mechanisms of changes in etching characteristics have been investigated and discussed with the emphasis on adlayer formed on etched surface.

In situ ellipsometry at selected wavelengths in the spectral range 280 nm to 1000 nnn was performed during the rf bias assisted electron cyclotron resonance (ECR) etching of bulk silicon, GaAs, InP, and GaAs/AlGaAs/GaAs, and InGaAs/InP layered strcutures by a CCl2F2 based etch gas.

While real time thickness changes for bulk materials cannot be determined ellipsometrically, some insight into the etch mechanism may be gained by observing the effect of the process on the surface dynamically, and after the etch process has been completed. Monitoring of the layered structures during etching can provide a real time measure of the amount of material remaining in the layer being etched, and provide tight process control.

Aluminum oxide films have been deposited by electron-beam evaporation on heated substrates under oxygen ion bombardment. Substrates were crystalline silicon, grafoil and glass. Both substrat temperature and ion current density were changed for each deposition The films deposited on silicon were examined by spectroscopie ellipsometry which showed that for substrate temperatures between 70°C and 250°C the index of refraction, and therefore the film density, first rose and then decreased with increasing ion current density. Ai 400°C the index reached a plateau under these conditions. Study by Rutherford backscattering of films deposited on grafoil showed no significant correlation between oxygen-aluminum stoichiometry and fi; density, suggesting that the decrease in density for large ion currei is not due to oxygen-ion incorporation, as has been suggested in the past. The films deposited on glass at 400°C showed some evidence of crystallization.

We have studied the conditions for effective removal of H from the silicon (100) surface by Ar and He plasma bombardment as a function of pressure, plasma power and time. At a given pressure, a range of rf plasma powers exists for effective H-desorption. For example, at 250°C and for 100 mTorr of He, H is desorbed only between 12 and 50W of plasma power. The range of effective powers was found to become narrower with increasing pressure. We have also found the efficacy of the H-plasma clean to be reduced by addition of He and Ar. Substrate damage results from Ar addition and from increased plasma power for pure H. The results are discussed along with Langmuir probe analysis of the various plasma conditions.

We have studied the epitaxial growth of MgO single crystal thin films by depositing Mg onto MgO substrates in an oxygen atmosphere. This method provides a simple way to dope Mg18O layers uniformly into Mg16O. The well controlled layer thicknesses are suitable for bulk diffusion studies both in the MgO epilayer and the MgO substrate. The MgO growth rate was measured and found to be proportional to the Mg flux and to the square root of oxygen pressure at a given temperature, obeying the law of mass action. High quality MgO single crystal thin films, as indicated by RHEED and x-ray diffraction, were found to grow over u wide temperature range, as in the earlier work1 using e-beam evaporation.

We report highly resolved, damage-free etching of GaAs and related materials. The etching is activated by excimer laser irradiation at 193 nm of samples maintained at low temperatures (∼140 K) in a chlorine atmosphere (∼5 mTorr). Since the etching is chemical in nature, structural damage to the substrate should not be present. Submicrometer resolution has been achieved by the use of electron beam lithography to pattern a Si3N4 contact mask. We have also successfully used our etching in the fabrication of a single-quantum-well, ridge-waveguide semiconductor laser.

Amorphous carbon films were prepared by the ion beam deposition of methane saturated with silicon pump oil 704. The concentration of Si in the ion deposited coatings could be varied by the temperature of silicon oil bath where saturated vapor was produced. In the process, the vapor ionized at 800 V was accelerated and impinged on glass or stainless steel substrates at ion densities between 0.3–1.5 mA/cm2 for a period of less than 60 minutes. The resulting films were characterized by x-ray photoelectron and Raman spectroscopies. The elemental components of these films include carbon, oxygen and silicon with varying amounts of nitrogen, iron and tungsten contaminations. The microstructure mainly consists of tiny graphitic carbon with sp2 ordered and disordered configurations, numerous carbon-oxygen and carbon-silicon linkages. This simple unique process yields a homogeneous thin coating suitable for many tribological applications.

The ionized cluster beam (ICB) deposition was use to stabilize the metastable zinc-blende (ZB) MnTe films directly on GaAs (100) substrates at 300 °C with MnTe cluster ion beam. Influences of the ionization and the acceleration voltage on film properties were investigated by the reflection high-energy electron diffraction (RHEED), optical reflection, Raman scattering, and photoluminescence. The ZB-MnTe was stabilized by 3kV acceleration of the MnTe cluster beam. These results showed that the ICB deposition is useful to get compounds having crystalline phase different from the structures observed io equilibrium-grown bulk crystals.

Electron cyclotron resonance (ECR) argon plasma has been used (to etch the native oxide on Si and thermal SiO2. The Schottky barrier height modification on both n- and p-Si has been studied as a function of substrate bias and etch time. Deep Level Transient Spectroscopy (DLTS) measurements show clear peaks on both p- and n-Si, but wish low levels of trap concentrations (1012-1013cm−3), and decreasing with depth from the surface. The effects of thermal oxide etching on the Si/SiO2 interface have been estimated with MOS capacitors. Negative flat-voltage shift is observed after argon plasma exposure, which removes the thermal oxide at a rate of over 100 Å/min at 50 V bias. C-V measurements show an order of magnitude increase in interface trap density.

A study on ion beam synthesis of buried α- and β-FeSi2 in >100< Si is presented. Phase formation has been investigated as a function of implant and anneal temperature. Layer characterization was performed by RBS, XRD, resistivity, spreading resistance and Hall effect measurements. Orientation effects in the layers have been observed depending on the implant temperature. Transport measurements show that die holes are the majority carriers in the semiconducting layers.

Synthesis of buried, epitaxial CoSi2 layers in Si1−xGex alloys (x =0.48 and x = 0.09) by 100 and 150 keV Co+ ion implantation and subsequent rapid thermal annealing was studied by X-Ray diffraction, Rutherford backscattering spectroscopy, He ion channeling, Auger Eectron Spectroscopy and Transmission Electron Microscopy. Buried single-crystal CoSi2 layers in the Si0.91Ge0.09 alloy containing ≈ 1 at% Ge were formed. The suicide formation causes an outdiffusion of Ge leading to an increase in the Ge concentration of the adjacent SiGe layers. In contrast, in the Si0.52Ge0.48 alloy no buried suicide layers could be produced.

Transition metal suicides are receiving an increasing amount of attention as materials for VLSI interconnects because of their low resistivities and ease of integration with silicon. A recently invented technique, mesotaxy, allows the production of buried single-crystal suicide layers in silicon.

Buried suicide layers made by implantation into (100) Si wafers can be patterned by restricting the implant with an oxide mask, giving great flexibility in the types of features that can be produced. We have fabricated simple microstructures to investigate the formation and properties of mesotaxial CoSi2. Wires of constant dose but varying widths exhibit a transition in morphology from {111} faceted wires to largely (100) faceted layers. After annealing for prolonged periods, the finer wires show the effects of coarsening. We have also observed the movement of a significant amount of Co from the oxide implant mask into the substrate during these anneals. The wires show greatly improved thermal stability compared to polycrystalline suicides formed by deposition.1

The optical reflectivity from buried and exposed CoSi2 layers produced by Co ion implantation of Si substrates has been measured over the energy range 0.012–6.2 eV (0.2- 100 μm). Both unannealed and annealed layers were investigated. The complex dielectric constant of the bare CoSi2 layer was obtained from a Kramers-Kronig analysis. The plasma frequency, carrier concentration and relaxation time of the buried CoSi2 layers were obtained from classical dispersion analyses of the multicomponent reflectivity data. The effective carrier concentration derived from the optical data and the measured chaneling from Rutherford back scattering correlated with anneal temperature.

Dual implantation of cobalt and iron into silicon (100) wafers and subsequent annealing has been used to form layers containing mixtures of CoSi2 and FeSi2. The structure and properties of the layers were followed by Secondary Ion Mass Spectrometry (SIMS), cross-sectional transmission electron microscopy (XTEM), Transmission Electron Diffraction (TED), Rutherford Backscattering Spectroscopy (RBS), and photoluminescence (PL). When a high dose of both species was implanted, segregation of the cobalt and iron occurred which for 1000°C anneals, resulted in an epitaxial layer of αFeSi2 upon a CoSi2 layer. The epitaxial quality of both of these layers was superior to those previously fabricated by single species implants. For a low dose cobalt implant followed by a high dose iron implant, a single phase solid solution was formed and segregation did not occur. Photoluminescence at 1.54 urn was observed from this layer, but with a much lower intensity and a broader line width than that from a pure βFeSi2 layer.

An unusual Ni distribution with two completely separated buried and surface suicide layers has been observed after Ni ion implantation in Si(111) kept at a temperature of 300° C, with a dose of 1.1 × 1017/cm2 and at a fixed energy of 90 keV. RBS/channeling, AES and cross-sectional TEM have been used to study this phenomenon as a function of the substrate temperature and Co co4mplantation. A model is presented, based on the diffusion of the transition metal, the defect annealing during the implantation, and the gettering power of the surface and the end of range defects.