Hydrogen can influence the behaviour of materials significantly. The effects of hydrogen are specially pronounced in high fugacities of hydrogen which can occur at the surface of steels in contact with certain aqueous environments. In this investigation the effect of high fugacity hydrogen on the surface of stainless steel was investigated using electrochemical cathodic charging. Microhardness was measured on the cross section. Transmission electron microscopy was used to investigate the dislocation substructure just below the surface. Computer simulation using finite element method was carried out to estimate the extent and severity of the deformation. The significance of the results are discussed in relation to the loss of ductility due to hydrogen.

A high pressure gas atomization (HPGA) process has been employed to study microsegregation in LaNi4.75 Sn0.25 and LaNi4.6Si0.4 alloy powders to serve as a basis for further investigations of low cost production of multicomponent alloys in combination with mishmetal (Mm). This investigation is an attempt to produce high quality powders for battery cathode fabrication that can be used in an as-atomized condition without prolong annealing, hydridingdehydriding, and grinding. Argon atomizing gas was used in the HPGA process of the LaNi4.75Sn0.25 and LaNi4.6Si0.4 alloys to investigate rapid solidification effects on microsegregation. Short annealing treatments of 5 minutes at 900°C were able to homogenize both alloy compositions, eliminating solidification micro-segregation along the grain boundaries phases. The rapid homogenization can be attributed primarily to the refined cell structures in gas-atomized particles that provide short diffusion pathways for the dissolving elements.

An alternative approach for modeling the hot carrier degradation of the Si/SiO2 interface based on the dispersive characteristics of the interface trap generation has been proposed. The timedependent interface trap generation has been modeled using the stretched exponential expression. The conventional power law of degradation is just the approximation of this general form. Very good agreement has been found between the theoretical model and the experimental data. This approach gives more physical insight into the understanding of the mechanism for the interface trap generation.

The interaction of hydrogen (deuterium used as tracer) with Si-Si02-Si buried oxide layers (BOX) prepared by thermal oxidation or by oxygen implantation (SIMOX) are investigated using Secondary Ion Mass Spectrometry (SIMS) measurements combined with effusion experiments. The sample deuteration is performed at different temperatures between 150 and 300°C using a radiofrequency plasma. In SIMOX samples, the deuterium diffusion profiles analysed by SIMS show deuterium trapping on implantation defects, and deuterium diffusion in the silicon substrate by permeation through the oxide layer for temperatures higher than 250°C. The deuterium is still detected in the buried oxide layers after isothermal annealing at 600°C during 2 hours. The deuterium trapping at the siliconsilicon dioxide interfaces is analysed.

Passivation of the SiO2-Si interface by hydrogen/deuterium in MOS transistors serve to ensure their operating reliability against channel hot carriers. Physical characterization of device sintering process in deuterated forming gas (10%D2:90%N2) is carried out by dynamic SIMS on planar CMOS gate stack structures, in conjunction with device hot carrier electrical testing. It is found that incorporation of deuterium in the doped poly-Si/SiO2/Si interfacial region readily occurs under typical post-metallization sintering conditions, demonstrating that transport of deuterium through CMOS gate is an effective pathway in an encapsulated device structure with silicon nitride sidewalls. The measured Si-D areal densities in the interfacial region depend on gate poly-Si doping type, but in both cases, appear to be sufficient to achieve complete interface Si dangling bond (˜1012 cm−2) passivation for the SiO2-Si system.

The interaction of deuterium with silicon-implanted-with-oxygen (SIMOX) was studied for samples with and without silicon top layer using thermal desorption measurements. Deuterium is incorporated in the buried oxide by disruption of the Si-O bridging bonds. The data reveal that the top layer reduces the uptake at 1073K. Furthermore, it retards release; a moderate (≈125K) and a high-temperature (≈1400K) retention were observed. It is proposed that release is accompanied by the reconstruction of the Si-O bonds and that the bare oxide surface constitutes an abundant source for defects thus enhancing the generation and elimination of Si-O bridging bond defects.

The incorporation of hydrogen into standard p-type Czochralski (Cz) silicon (≥1 Ωcm) by a 110 MHz plasma treatment at 260°C leads to the formation of an n-type region due to hydrogen enhanced thermal donor (TD) formation in hydrogenated regions of the wafer, if a subsequent annealing in air is applied at 450°C. Spreading resistance probe (SRP) and light beam induced current (LBIC) measurements were used for the experimental analysis. The p-n junction depth, i. e. the counter doping by TDs, depends on the initial doping level of the p-type substrate, and therefore on the post-hydrogenation annealing time. The penetration of the n-type region into the wafer bulk is driven by a rapid hydrogen diffusion. The essential process for a TD generation is the creation of metastable hydrogen molecular species around 260°C and their decay at 450°C.

A summary is given on the electrical properties of transition-metal hydrogen complexes in silicon. Contrary to the general understanding, hydrogen leads not only to a passivation of deep defect levels but also creates several new levels in the band gap due to electrically active transition-metal complexes. We present detailed data for Pt-H complexes and summarize briefly our results on the transition metals Ti, Co, Ni, Pd, and Ag. The introduction of hydrogen at room temperature by wet chemical etching, followed by specific annealing steps allows us to study the formation of the different complexes. In particular, depth profiles of the defect concentrations give an estimate of the number of hydrogen atoms involved in the complexes. Transition-metals binding up to four hydrogen atoms are identified.

We studied the interaction between hydrogen (H) and Zn or Zn-related defects in Zn-doped Si crystals from the measurements of optical absorption spectra of hydrogen bound to Zn or Znrelated defects. We doped Si crystals with Zn by annealing the crystals in Zn vapor at 1200°C followed by quenching. After Zn-doping, we doped specimens with H by annealing them in a hydrogen atmosphere followed by quenching. We measured optical absorption spectra of the above specimens at about 6 K by means of FT-IR spectrometry. Many optical absorption peaks were observed; some are due to electronic transitions and some are due to vibrational transitions of H vibration. Hydrogen atoms are known to passivate Zn acceptors since the optical absorption intensity associated with electronic transitions become much weaker after hydrogenation. Absorption peaks associated with H vibration are known to be related to complexes composed of one Zn atom and two hydrogen atoms. We concluded this from studies on the effect of co-doping with H and deuterium and the effect of Zn isotopes on the optical absorption spectra due to H.

Interaction of hydrogen atoms and vacancy-related defects in 10 MeV electron-irradiated n-type silicon has been studied by deep-level transient spectroscopy. Hydrogen has been incorporated into electron-irradiated n-type silicon by wet chemical etching. The reduction of the concentration of the vacancy-oxygen pair and divacancy occurs by the incorporation of hydrogen, while the formation of the NHI electron trap (Ec – 0.31 eV) is observed. Further decrease of the concentration of the vacancy-oxygen pair and further increase of the concentration of the NH1 trap are observed upon subsequent below-band-gap light illumination. It is suggested that the trap NHI is tentatively ascribed to the vacancy-oxygen pair which is partly saturated with hydrogen.

Silicon samples were implanted with 100 keV hydrogen at doses ranging from 4.9 to 9.9 × 1016 H/cm2. The samples were then annealed in an argon atmosphere using a special furnace mounted on a microscope stage. The time required to observe the onset of Si blistering was then measured as a function of temperature for the various hydrogen doses. An Arrhenius plot of the time-temperature data was made and an “activation energy” was calculated for each dose. The measured activation energies range from 2.6 to 1.1 eV corresponding to 4.9 to 9.9 × 1016 H/cm2, respectively. A qualitative explanation of the dose dependence is given in terms of a stressinduced lowering of the Si-Si bond energy. The hydrogen distribution as a function of annealing temperature was monitored using the 1H(15N,αγ)12C nuclear reaction. The results from the hydrogen profiling indicate that the hydrogen profile flattens at 500°C and concentrates at 550 °C.

Infrared multiple internal reflection (MIR) spectroscopy was used to investigate the local chemical bonding in sub-surface defects induced by remote hydrogen plasma exposure (RHPE) of Si(100) wafers. Exposure of very lightly doped n-type Si ([P] =; 5 × 1013 cm−3) to a remote hydrogen plasma for 2 min at 200°C results in the formation of Si monohydride species. An intense narrow band at 2078 cm−1 (FWHM = 7 cm−1) and a small shoulder at 2065 cm−1 are observed. The data are consistent with monohydride termination of Si{111} platelet defects with a weak interaction between H atoms on opposing internal surfaces. In contrast, platelet nucleation at 200°C followed by growth at 300°C selectively generates Si dihydride species, as evidenced by a single broad infrared band at 2109 cm−1. The P concentration was found to have a marked influence on the areal density and chemical bonding of sub-surface hydrogen. The MIR spectrum of lightly doped Si ([P] = 2 × 1014 cm−3) after RHPE at 200°C contains broad peaks at 2078 and 2130 cm−1 consistent with Si monohydride and trihydride species. We infer that hydrogen saturates broken bonds along Si{111} Type I glide planes (one bond per Si atom) and along Si{111} Type II glide planes (three bonds per Si atom). The Si-H peak area indicates a H areal density ∼2 times higher than in very lightly doped Si.

The hydrogen binding energy distribution and IR spectra of hydrogen platelets in c-Si have been measured and compared to H in other forms of silicon including hydrogenated polycrystalline and amorphous Si. The binding distribution for platelet containing samples, determined using H evolution, exhibits two peaks: a bulk peak at 1.8–1.9 eV below the transport barrier, and a second possibly surface related peak 1.8–1.9 eV below the surface evolution barrier. The bulk peak grows at 250C and is consistent with calculated energies for platelet structures. The same two evolution peaks are found in hydrogenated polycrystalline Si and amorphous silicon. The IR spectra for heavily hydrogenated c-Si are dominated by the stretching modes at 2076 and 2128 cm-1. Most surprisingly there appears to be a strong mode at 856 cm-1 which is associated with a deformation mode of SiH3. Even more surprising, this SiH3 856 cm-1 mode remains until 550 C indicating that the SiH3 containing structures are rather stable.

In this work the mechanism of hydrogen incorporation and structural stability of a-Si:H films deposited by LF 55 kHz glow discharge in a wide range of technological parameters have been investigated. The analysis of plasma emission spectra and microstructure of films measured by IR spectroscopy and atomic force microscopy were carried out. It was shown that hydrogen desorption controls the growth rate in a wide range of substrate temperature (40–325°C ) and at low values of LF power (50–200W). At the same time the abnormal increase of hydrogen content due to ion-molecule surface reactions with the increase of substrate temperature was observed. The kinetics of hydrogen diffusion and thermodynamics of defect formation in a-SiH films were determined from modeling of differential scanning calorimetry data. It is concluded that the mechanism of hydrogen incorporation leads to formation of strong Sill bonds in the material bulk and to increase of structural stability with the increase of substrate temperature despite of the increase of hydrogen content.

Microcrystalline silicon samples were exposed to an electron cyclotron resonance (ECR) hydrogen plasma at various exposure times and substrate temperatures. Before and after each post-hydrogenation treatment the crystalline fraction, Xc, was determined from Raman backscattering spectra. The results reveal that the change of Xc strongly depends on the structural composition of the starting material. Amorphous samples exhibit an increase of Xc while for ltc-Si specimens the Xc decreases. The decrease of Xc is enhanced for specimens with a high initial crystalline fraction. The same plasma treatment of Si-wafers did not lead to amorphisation. We conclude that the presence of lattice strain is required to observe a H-induced decrease of Xc.

Si(100) is H-passivated via a modified pre-RCA cleaning followed by etching in HF:alcohol, to produce ordered (1 × 1) templates which desorb at low temperature (T ≥ 600°C). Four sets of 12 wafers, each set processed identically, are used to test reproducibility, and are characterized by Ion Beam Analysis (IBA), Tapping Mode Atomic Force Microscope (TMAFM), and Fourier Transform Infrared Spectroscopy (FTIR). The absolute coverage of oxygen and carbon is measured by ion channeling combined with nuclear resonance at 3.05 MeV for oxygen and 4.265 MeV for carbon, improving the signal to noise by a factor 10 for oxygen and by 120 for carbon. It is then possible for the first time to measure ordering of oxygen atoms with respect to the surface by comparing the amount of oxygen from rotating random spectra to the disordered oxygen measured by channeling. Hydrogen is measured via the elastic recoil detection (ERD) of 4He2+ at 2.8 MeV.

Si(100) etched in HF:methanol after a modified preliminary RCA cleaning yields the cleanest surface. The data suggest that Si(100) passivated by HF in alcohol is terminated by an ordered hydroxide layer, which desorbs at lower temperatures than the more refractory Si02.

Hydrogen is a detrimental impurity in many chemical vapor deposited (CVD) materials, particularly those involved in electronic or optical applications. For example, active hydrogen defects have been observed in materials such as silicon, Si, gallium arsenide, GaAs, and diamond, C, thin films. Hydrogen and its related defects can be identified, quantified, and observed using magnetic resonance techniques. These techniques allow a unique quantitative, non-destructive view of hydrogen in the solid-state. Nuclear magnetic resonance (NMR) is used to study hydrogenated defects directly, while electron paramagnetic resonance (EPR) is used to observe hydrogen associated with paramagnetic defects. These observations can enhance our understanding of the effects of hydrogen incorporation on the properties of such materials.

23Na and 1H NMR studies have been carried out for a NaxHyC60 superconductor The peak position of the 23Na NMR spectrum exhibits discontinuous upfield shift of 30 ppm at about 250 K, indicates a first order phase transition From the line shape of the 23Na spectrum obtained at 7 K, the quadrupole coupling constant tensor is evaluated to be |e2Qq/h|=3.7 MHz with the asymmetry parameter η = 0.95. The 1H NMR spectrum suggests an anionic hydrogen state with weakly delocalized nature.

An etching process of hydrogen ions was performed during the initial growth stage of diamond films. The H+ ion etching was performed by applying a negative substrate bias during a microwave plasma chemical vapor deposition process, using only hydrogen as a reactant gas. The contribution of H+ etching under different substrate bias and for different etching time to the orientation degree of diamond films was investigated by scanning electron microscopy and atomic force microscopy. It was found that an additional H+ etching process had influence on the orientation degree of deposited (001)-oriented diamond films. To achieve a significant improvement of crystal orientation, the bias voltage and etching time should be adjusted concerning to the situation of diamond films.

Mass spectrometry and calorimetry experiments on hydrogen evolution in amorphous Si:H and SiC:H nanoparticles grown by Plasma-Enhanced Chemical-Vapor Deposition (PECVD) are reported. The evolution spectra in a-Si particles are very similar to those found in films. The dynamic constants of the low-temperature peak confirm that this process is the same as in films. It is argued that the high-temperature process may not be diffusion-controlled. Both processes are exothermic, indicating that most dangling bonds recombine after H-desorption. The Hevolution in SiC occurs at higher temperatures than in Si. The process is endothermic.