Ultraviolet radiation has been used to anneal out extrinsic defects in several types of deposited a-SiO2 films. The UV light was obtained from a new krypton UV-VIS-IR lamp with a spectral range of 170 nm < λ, < 3 μm. This “cold” annealing was performed on a-SiO2 films with various thicknesses up to 400 nm. The films were deposited by various techniques, ultraviolet induced chemical vapour deposition (UVCVD), plasma enhanced vapour deposition (PECVD) and spin-on-glass (SOG). Fourier Transform Infra-Red spectroscopy (FTIR) and Electron Spin Resonance (ESR) were used to characterize the effect of the radiation. In the case of UVCVD and SOG a-SiO2 films, it is shown that the UV radiation removes the Si-H bonds and reduces significantly the amount of C-H and C-H3 groups. In both these films, an important reduction in the amount of adsorbed water and Si-OH groups is observed, together with an increase in the number of Si-O bonds. In PECVD films made with tetraethylorthosilicate (TEOS) vapour and O2 as precursor gases, we find evidence for an important reduction in the amount of C and the number of CnHy related defects. The UV treatment is effective even at temperatures as low as 100 °C, which suggests that it could constitute a much needed low temperature annealing step.

Photodissociation of trimethylaluminum molecules with a UV lamp is shown to be an effective technique for predisposing the irradiated silicon surface prior to subsequent aluminum film growth via visible laser induced pyrolysis. The Al deposits thus obtained are carbon contamination free. The UV exposure time needed for the onset of Al nucleation and growth is deduced from an in situ laser reflectometry technique. Direct laser writing is obtained using this two-step process and a microscopic analysis of the lines is made in correlation with the experimental procedure.

Phosphorus and beryllium have been coimplanted in InGaAs. Various anneals have been performed in the temperature range of 745–826 °C. The secondary ion mass spectrometry measurements have revealed anomalous redistribution of the beryllium dopant: “up-hill” Be diffusion profiles have been observed. The observations of as-implanted profiles suggest that these anomalous beryllium peaks are due to beryllium trapping by the extended defects generated by the P implantation. A good agreement has been obtained between the experimental data and simulated profiles.

We study the surface dynamics of silicon nitride films deposited by UV-induced low pressure chemical vapor pressure. Atomic force microscopy measurements show that the surface reaches a scale invariant stationary state coherent wit the Kardar-Parisi-Zhang (KPZ) equation. Discrete geometry techniques are oriented to extra morphological characteristics of surface and bulk which corresponds to computer simulated photodeposit. This allows to determine the physical origin of KPZ scaling to be al ow value of the surface sticking probability, and connected to the surface concentration of activate charged centers, which permits to start the evaluation of the Monte Carlo-molecular dynamics simulator.

Controlled and reproducible fabrication of nano-structured materials will constitute one of the main industrial challenges for the next 10 years. To overcome the severe limitations of existing nano-fabrication techniques, we have developed and improved the ultimate usable resolution of an innovative focused ion beam instrument (FIB). In this work we demonstrate that FIB techniques allow quite simple, direct, clean and reproducible material nano-structuring close to or below the 10 nm level.

The main characteristics (sensitivity, response time, dynamic range) of a photoconductive detector (PCD) depend on the intrinsic physical (lattice parameter, extended and local defects) and electrical properties (resistivity, mobility, carrier lifetime) of the material. Selection criteria for semi-insulating undoped gallium arsenide (GaAs) were thoroughly examined for their capacity to select the more suitable material for the fabrication of fast PCDs, used in gamma-ray pulse (E∼1.2 MeV, τFWHM=30 ns) metrology. An analytical model, which assumes that carrier recombination takes place through EL2 type recombination centers [M. O. Manasreh and B. C. Covington, Phys. Rev. B 35, 2524 (1987)], was developed. Taking into account the initial physical and electrical properties of the GaAs material, the model accurately predicts the response of the PCDs after a neutron preirradiation step (dose range: 5×1014 to 1×1016 neutrons/cm2), which was used to optimize the PCD characteristics and in particular to reduce the response time to values lower than 100 ps. This led to the identification and validation of key parameters of the initial properties of single crystal GaAs materials influencing the PCDs final characteristics. Thus, depending on the user defined specifications, GaAs material initial properties and neutron preirradiation dose can be fixed to fabricate GaAs PCDs exhibiting the desired response time, sensitivity, and dynamic range. The study established that the PCDs characteristics are controlled only by the initial GaAs material properties when neutron preirradiation doses remain below 1×1015 neutrons/cm2, whereas they are mainly controlled by neutron induced crystal defects above this dose.

Surface atomistic structures of a-SiN:H vacuum ultra violet (VUV) photodeposited on InP(100) have been investigated by using atomic force microscopy (AFM) and index of refraction (RI). After simultaneous VUV irradiation (185 nm) and heating (400–650 K), the onset of nucleation shown SiN:H islands on the InP substrate prior to the deposition stage. We have proposed a new photodeposition model taking into account the molecular dynamics (MD) of the adsorbed species imposed to a Monte Carlo (MC) computation technique. Features estimated or obtained through experimental validation are emphasized. This allows the evaluation of both the simulator and physical model. Also deposition kinetics, in addition to surface and bulk features, are clearly evidenced and simulated in 3-D images. To this end, we developed analytical tools to exactly track discrete boundaries of the deposition bulk and pores from simulation data, in the form of voxels for each site of the face centered cubic (fcc) referential. These tools use a discrete-topology approach to isolate, count and measure individual pores, as well as the top surface features. Discrete neighborhoods in the fcc referential are also considered in the framework of the mathematical morphology in order to correctly measure discrete approximations of Euclidean surface and other morphological parameters. These tools helped to quantify the simulator results, in order to compare them with experimental data and also validate the physical model. 3-D visualization of surfaces and pores further aided us to see in an organized fashion the output of the simulator, e.g. by sorting pore features by size, or location in the bulk.

Real-time Monte Carlo Molecular Dynamics (MC-MD) simulation techniques have been developed to model the nucleation, the initial stages of growth, and thin film growth, during InP Molecular Beam Epitaxy (MBE) on InP. The simulation mode includes tetrahedral lattice coordination, species-species interactions out to third-nearest neighbor, heterogeneous photolysis of precursors molecules on vacuum UV, adspecies migration on the lattice, nucleation on conventional and charge activated centers, and desorption dynamic effects. An InP homoepitaxy system, permits the simulator validation against MBE experimental results; although the model and the corresponding simulator are easily applied to a variety of other problems. The amount of InP epitaxy as a function of time is obtained over surface are of 50 X 50 atomic sites. The result of the simulations demonstrate that model treatment is accurate and encompasses several improvements over previous treatments. The agreement between experimental and simulated roughness serves to build confidence in the use of Mc-MD for MBE studies.

We report on an accurate validation of a new Monte Carlo three-dimensional model. Simulations up to 1200 Å layer thickness have been carried out for amorphous thin film layers of SiN:H deposited at low temperature (400–650 K) on (100) InP, by vacuum ultraviolet (VUV, ∼185 nm)-induced chemical vapor deposition (CVD). The computer simulations in the mesoscopic-submicronic range are compared with atomic force microscopy and index of refraction measurements. The reconstituted surface roughness and the voids discrete representations of the bulk are found to be in good agreement with these measurements. Simultaneously at around 450 K (at ∼175°C), thermal characteristic evolution of the both surface roughness and bulk porosity showed a transition from rough to smooth deposition and from low to high density.

We detail a novel three dimensional (3D) patterning capability for focused ion beam technology which uses, as a resist, a gold cluster compound Au55(PPh3)12Cl6. The high-resolution 3D morphology of the patterned structures is examined and electrical characterization analyses are carried out. Patterns having minimal lateral dimension about 30 nm and vertical resolution below 10 nm, are displayed using this method. Direct writing speeds up to 3.6 103 μm/s were reached.

A solid-on-solid (SOS) model to simulate SiN:H dynamic surface characteristics in ultraviolet chemical vapor deposition (CVD) onto indium phosphide is presented. It is recognized that the nucleation process occurs at an UV induced active charged center on the surface of the substrate. Photolysis rates are determined using bond dissociation energies for molecular processes to generate active adsorbed species. The microscopic activation energy in elementary processes depends on the configuration of neighbouring atoms. Monte Carlo–Metropolis method using microscopic activation energy barriers is taken into account in molecular processes by a three-dimensional algorithm. The model includes lattice coordination and atom–atom interactions out to third-nearest neighbours. The molecular events are chosen with a probability of occurrence that depends on the kinetic rates at each atomic site. Stable incorporation of main species is enabled. Three-dimensional simulation of a growing interface indicates validation of a thermally activated rough–smooth transition for submicronic thick layers in the Kardar–Parisi–Zhang model.

We have investigated the influence of spontaneous low frequency oscillations (LFO, f∼0.01 Hz) occurring at high electric field (>1kV/cm) in resistive photoconductors (PCD) made from semi-insulating GaAs on the response of the PCDs under pulsed gamma-ray irradiation (E∼1.2 MeV, τFWHM=30ns). The PCDs were fabricated using GaAs from five commercially available sources. The PCDs were irradiated with fission neutrons in order to reduce their response time down to less than 100 ps. The amplitude of the LFOs was found to be related to the carrier lifetime, and thus defect concentration in the GaAs material. It was larger for material exhibiting high carrier lifetime. Increasing the localised defect concentration, such as EL2 type defect, through GaAs irradiation with fission neutrons was found to decrease the amplitude of the LFOs. PCDs irradiated at high neutron doses (>1×1015 neutrons/cm2) showed no LFOs. It is suggested that interactions between the propagating domains and the highly defective GaAs bulk control the LFO characteristics. Gamma-ray sensitivity, in transient mode, versus bias voltage of PCDs was also found to be correlated to LFOs, showing that high-field behavior of GaAs can be used to predict the optimum operating bias of the PCDs.

Microstructural changes of surfaces and bulk of a SiN: H were investigated at the atomic level by a simulator. The simulator is based on a solid-on-solid type model for ultraviolet localized-chemical vapor deposition. The calculations consider the well-defined photolysis products adsorbed at atomic sites. Incorporation of main species is enabled by a Monte Carlo-Metropolis simulation technique. Photodeposition rates are obtained using bond dissociation energies. In this manner, the dependence of root-mean-square deviation of surface roughness and bulk porosity on operating conditions can be predicted. Photonucleation and photodeposition with a UV low pressure mercury lamp at low pressure and temperature were simulated onto indium phosphide substrate.

A model for ultraviolet induced chemical vapor deposition (UV CVD) for a-SiN:H is described. In the simulation of UV CVD process, activate charged centers creation, species incorporation, surface diffusion, and desorption are considered as elementary steps for the photonucleation and photodeposition mechanisms. The process is characterized by two surface sticking coefficients. Surface diffusion of species is modeled with a gaussian distribution. A real time Monte Carlo method is used to determine photonucleation and photodeposition rates in nanostructures. Comparison of experimental versus simulation results for a-SiN:H is shown to predict the morphology temporal evolution under operating conditions down to atomistic resolution.

Le développement d'une nouvelle source d'irradiations à éclairs modulable en longueur d'onde, a ouvert la voie à de nouvelles techniques de dépôt activé par photons.Ces techniques exploitent la possibilité pour certaines sources de fournir des irradiations combinées en ultraviolet lointain, en rayonnement visible et en infrarouge dans la gamme 160-5000 nm.Un paramètre important est la durée de l'irradiation impulsionnelle (inférieure à 30 microsecondes).La puissance de la source que nous décrivons ici dans l'ultraviolet lointain permet de réaliser à la fois le nettoyage, le dépôt et le recuit des diélectriques à basse température (<400 °C ) sur Si et InP.Nous décrivons plus particulièrement la réalisation de couches minces de SiO x N v peu hydrogénées et exemptes de radicaux OH et d'eau.Nous montrons que les qualités obtenues par cette technique sont intrinsèques aux mécanismes élémentaires des dépôts photolytiques.

Gold nanograins of dimensions ranging from 1 to 4 nm are deposited from a liquid metal ion source at variable landing energies. The distribution of nanograins can be selected by wisely playing with the parameters governing the deposition like the energy of the incident particles (500 eV - 10 keV), the emission current of the source (20 μA – 100 μA) and the deposition time (10 s – 45 s). The results of both dimensionality and pitch shows the potentiality of this technique to produce very small metallic islands of high stability suitable for fabricating metallic Coulomb blockade devices.

SiOxNy for micro- and optoelectronics is obtained from a low-pressure vapor deposition reaction induced by a novel flash lamp which irradiates a precursor mixture NH3/SiH4/N2O in deep ultraviolet (160-260 nm) and IR Amorphous thin films are resulted within the composition of silicon oxynitride. Flow ratio of precursors and flashtubes were varied to produce a range of x and y. The detailed properties have been investigated using ellipsometry, infrared absorption, Auger electron spectroscopy, and Atomic Force Microscope. The hydrogen concentrations, as N-H bonds, were low, in the range (2 - 5)10(23) H atoms.cm(-3). All samples deposited at 400 degrees C are isotropic and homogeneous in hydrogen content. No absorption bands of O-H, Si-H and H2O are detected in the range of the FTIR spectra. A Monte Carlo type model is well adapted to simulate the morphology tendencies for SiOxNy film isotropy improvement.

Silicon oxynitride, SiOxNy (x, y ∼), grown by flash deep-ultraviolet chemical vapor deposition (FUV CVD) has attractive optical, electrical, mechanical and chemical properties which make it a suitable dielectric with low dielectric constant for both microelectronics and photonics applications. At low temperatures (300–400°C) large area nearby-stoichiometric films are deposited. At different precursor flow ratios, SiOxNy films are obtained with variable x and y. This allows variation of optical functions with x and y. FUV CVD films are low in hydrogen and free of water and hydroxyl. Since the deposition temperature is significantly lower than that observed in other conventional techniques, they are essentially free of stress.

A novel technology of excimer lamps has been applied to improve the properties of silicon oxide films by VUV photon annealing. Silicon oxide films were deposited at low temperature by ArF laser-CVD in parallel configuration using SiH4 and N2O as precursors. Post-deposition irradiation by VUV photons provided by a Xe excimer lamp (λ = 172 nm) at room temperature and in an inert atmosphere was performed. The films were characterized by Fourier transform infrared spectroscopy (FTIR), single-wavelength ellipsometry and electron spin resonance (ESR) to analyze the changes in the composition, the refractive index and the paramagnetic defects in the film structure. The VUV irradiation time was successively increased until saturation of film properties was reached. As observed by FTIR, the Si-H and Si-O bands show a clear evolution. While the Si-H bonds are broken until reaching their total elimination, an increase in the number of Si-O bonds takes place. These results are in agreement with the ellipsometric measurements in which a decrease in the refractive index towards stoichiometric values (n = 1.46) is observed. Moreover, ESR measurements show an increase in the concentration of paramagnetic defects in the structure by the VUV photon annealing, reaching a lower saturation value in comparison with samples obtained by other deposition methods.