The applicability of the nonlinear optical technique of surface second-harmonic generation to in-situ studies of epitaxial and non-epitaxial crystal growth of centrosymmetric materials is demonstrated. In measurements of the deposition of atomic Si on Si(111)-7×7 surfaces, the (anisotropic) second-harmonic response is seen to be sensitive to the ordering of fractional monolayers of adatoms. For deposition on a substrate held at room temperature, the second-harmonic data are consistent with the formation of a disordered adlayer on top of the original reconstructed surface. The results of real-time measurements of the thermal annealing of disordered Si adlayers of monolayer thickness are also presented.

In this paper, cross-sectional TEM is used to investigate the quality of silicon epitaxial films grown by ultra-low pressure chemical vapor deposition at 750°C. The dislocation density and epi.- substrate interface width were investigated for different predeposition Argon sputter cleaning condltions. Epitaxial films with dislocation densities of less than 10 cm−2 and interfacial width of about 13 Å were obtained.

Thermal desorption spectroscopy (TDS) is used to quantify the amount of hydrogen in hydrogenated amorphous silicon(a-Si:H) as well as to determine the binding state. It is possible to measure the quantity and binding state of hydrogen in 100–8000Å thick a-Si:H films. Hydrogen is incorporated in the 100Å thick film at a rate of about three times greater than that in the over 1000Å thick film. Hydrogen in all films is bonded to silicon with three kinds of binding states at 2.8, 3.1 and 3.3eV. a-Si:H:D is prepared from SiH4/D2 plasma in order to clarify the origin of hydrogen in the films which are usually deposited from SiH4 and diluted H2 gas. TDS spectra of H2, HD and D2 show that there is more hydrogen from SiH4 in the film in each of the binding states, than from the diluent H2.

Chemical vapor deposition of gold from dimethyl-2,4-pentandionato gold (III) and two fluorinated derivatives is reported. At substrate temperatures of 200–300°C, high purity gold films were obtained on SiO2 and Si substrates. Films with resistivities down to 1.3 times that of bulk gold were obtained at deposition temperatures of ∼200°C, where films with very small grain size could be deposited.

Electron irradiation of InP, InAs and InSb crystals within the electron microscope causes the crystallization of nearsurface amorphous material and the oxidation of bulk crystalline material. The material most commonly found in both regions is cubic In2O3, although small regions (< 5 nm) of the corresponding In-c 6mpound semiconductors are sometimes recrystallized. The observations are consistent with desorption of the anion species due to electron-beam-stimulated processes, with subsequent oxidation of residual In metal.

A CO2 laser, operating at 10.6μm, has been used to promote the growth of topotaxial layers of the chalcocite phase of cuprous sulphide in cadmium sulphide thin films immersed in an organic solution of a cuprous salt at ambient temperature. Cuprous sulphide growth is initiated by the laser beam which passes through the liquid and raises the surface temperature of the CdS allowing ion exchange to take place without changing the surface topography. An investigation into different combinations of organic solvents and cuprous/cupric salts has revealed that cuprous iodide in acetonitrile or propionitrile yields the fastest growth rates. The results are compared with those obtained from junctions fabricated using lasers operating in the visible frequency range.

A variety of materials such as semiconductors, metals, and insulators have been analyzed by use of the Hitachi IMA-3 ion microprobe analyzer. From the depth profile of a GaAs/AQ GaAs superlattice(50Å), a depth resolution of 45Å was obtained at 2350Å below the surface. The stable depth profile of a multilayer plastic film was obtained by using the negative ion beam(O) as a primary ion for charge neutralization. Further, the usefulness of the total ion monitoring method for correcting the changing factors of secondary ion intensity is demonstrated.

This study describes the application of a dc-plasma to stimulate growth of InP in a MOCVD system using In(C2 H5)3 and PH3. Precracking of PH3 enables a substantial reduction of the growth temperature to well below 500 K. In addition, at temperatures where InP is commonly deposited (∼870 K) a significant lowering of the V/III input ratio is possible. The fact that InP is relatively insensitive to low energy ion bombardement permits deposition in a canal ray configuration.

A model for dendrite growths in polycrystalline Si films formed during laser/plasma deposition with a silane discharge and a pulsed KrF laser has been developed. The model assumes a thin (less than 10 nm) amorphous silicon (a-Si) film is deposited on a substrate prior to phase transformation due to laser heating. The observed dendritic structure of the overall polycrystalline Si films is attributed to Si crystals shooting from an excessively supercooled Si liquid bath. Supercooled liquid forms since the melting point for a-Si can be reached at relatively low KrF laser fluences. Latent heat evolved at the solid-liquid interface induces an interface temperature higher than that of the melt and the requisite negative temperature gradient for absolute bath supercooling. Since the formation of an undercooled liquid by fast melting a-Si is also an important first step in explosive crystal regrowth studies, these results may have important implications for crystal growth and transient annealing. A conical approximation model is used in this study to characterize the stability of the dendrite tip in terms of local temperature gradients, i.e., the degree of undercooling at the tip of the parabolic dendrite. The degree of undercooling and hence the tip radius appears to be significantly affected by small changes in the laser fluence. Stability criteria lead to a relationship between regrowth velocity, V, and the tip radius, R, of the form VR2= constant. The size and stability of the dendrite tip is determined from a balance between the destabilizing force due to thermal diffusion and the stabilizing capillary force. Based on the observed tip radii formed at laser fluences from 0.13 to 0.25 J/cm2, the model predicts regrowth velocities in a range between 2.0 and 20 m/s – values consistent with transient annealing studies of a-Si

Hard carbon films have been deposited onto room-temperature silicon substrates in a de plasma of methane and hydrogen. The substrates are placed on the cathode. A stainless mesh is held at the same potential as the cathode and is set above the substrates. Although the deposited films are amorphous and contain 24.4 atomic percent hydrogen, they have the following diamondlike properties: hardness is almost equivalent to that of natural diamond; electrical resistivity is on the order of 1013Ωcm; chemical inertness is excellent to acids; thermal diffusivity is 5.2 cm2 /sec. However, the films have a large compressive stress of 1.3×1010 dyn/cm2.

Annealed films exhibit dehydrogenation, graphitization, an increase in chemical reactivity, volume expansion and stress relaxation above 400°C. The activation energy for the transformation from the diamondlikephase to the graphitic phase is 18 kcal/mole.

The dependence of the thermal diffusivity and hydrogen content on both the CH4/H2 gas mix ratio and the total pressure have been measured for the films deposited in a dc plasma without the mesh.

Tungsten films were plasma-deposited using an abnormal glow discharge through a mixture of tungsten hexafluoride, hydrogen, and argon. The films adhered well to silicon, silicon dioxide, gallium arsenide, and aluminum substrates placed directly on the discharge cathode. Typical deposition rates were on the order of 160 Angstroms/minute with as-deposited film resistivities of 40 to 70 microohm-cm. The tungsten was analysed using a number of techniques including X-ray diffraction, scanning electron microscopy, and Auger spectroscopy, Low-resistivity (<10 microohm-cm) films that adhered well to silicon-dioxide were obtained with a two-step process utilizing plasma deposition and conventional chemical vapor deposition.

The thin film growth of PbTiO3 by MOCVD has been investigated using both a pyrolytic process and a sputter assisted plasma deposition process. In the first process, lead tertiary butoxide and titanium iso-propoxide are introduced to a low pressure reactor simultaneously to deposit thin films containing lead and titanium onto a hot substrate (400–500 °C). In the alternative process lead is sputtered from a magnetron target in the presence of titanium isopropoxide vapour. Thin films containing lead and titanium are deposited onto a substrate which need not be heated. X-ray and EDAX analysis indicate the presence of Ti02 and elemental lead in the as grown layers. Oxygen annealing of ihese layers at 900° and 1100°C leads to the formation of polycrystalline PbTiO3 and where the substrate is silicon, a PbO/SiO2 glass phase.

The oxygen migration process during microwave-discharge plasma oxidation of Si is investigated using 18O as a tracer. The exchange phenomena between migrating oxygen and its counterpart in SiO2 are observed. When plasma grown oxide (Si 18O2) is further oxidized in 18O-enriched plasma. 18O is observed both at the SiO2 /Si interface and in the bulk of Si16O2. For the reversed case. i.e. Si18 O2 is oxidized in 18O plasma, the total amount of pre-existing 18O decreases. The suppression of 18O is more drastic in the surface region. These oxygen distributions indicate that oxygen migrates toward the interface accompanied by oxygen exchange.

Plasma nitriding of fused silica has been performed over a temperature range of 750°C to 1300°C in a nitrogen-hydrogen plasma generated by an inductively coupled RF discharge. The plasma is used as both thermal and chemical source. The effects of various process parameters such as surface temperature, gas pressure and treatment time on total nitrogen content have been studied. The advantages and the drawbacks of this direct plasma nitriding technique are briefly discussed.

Variations in refractive index (density) with growth temperature are taken as a rough measure of residual compressive stress in dry SiO2 films. This paper presents experimental data regarding the relaxation of these stresses by a low-temperature (600–900°C) oxygen corona discharge process. For an initial oxide layer of 1100 Å thickness grown at 800°C, relaxation is complete after a corona treatment of 10 minutes at -lμA. The dose of O− ions required is found to be about 1–1.5% of the total oxygen atoms in the initial layer. The difference in dose between oxide on (111) and (100) Si is found to be proportional to the respective density changes from the initial oxide to fully relaxed oxide.

A thermal plasma arc technique has been used to modify selected metallic surface and near surface properties at ambient pressures. This experimental study was implemented by treating several steel test specimens, at elevated temperatures, in a pure argon plasma and in two preblended argon/ active gas mixtures. One of the argon/active gas plasma mixtures produced significant chemical surface modifications in the steel test specimens treated in this atmosphere. Ions and free radical fragments, produced from the active gas, were responsible for the observed changes in the chemical composition of the steel surface. The other plasma treated specimens did not exhibit any changes in chemical specific details and results obtained, during this study, have been described.