Cel The amorphous state of insulating silicon oxynitride allows the synthesis of materials with a band gap that can be tailored continuously. The DESON Action aimed to provide the basis for new intermetallisation techniques by performing an in-depth study on insulating SiOxNyHz thin films. A complete set of experiments on samples of the same run have been performed. This gives a precise description of the amorphous network and enables the correlation of structural and chemical characteristics with the electronic and electrical properties.The electrical properties of thin-film insulating amorphous (non-crystalline) silicon oxynitrides SiOxNyHz were investigated. Samples of this material with varying composition (varying x, y and z) have been prepared, the structural, electrical and optical properties of the films measured, and the correlations between these properties studied. In addition, a theoretical model of the phonon and electronic densities was developed. The basis of new intermetallization techniques in very large scale integration (VLSI) technology is provided. A structure more chemically ordered than the RBM model for the silicon-oxygen and silicon-nitrogen bonds is probable for the medium range silicon oxynitrides. The hydrogen incorporation is also determined by a chemical ordering thermodynamic process instead of by a bond formation at random. The dangling bond formation is correlated with the appearance of local chemical configuration out of chemical equilibrium in the network. In the silicon oxynitride, the electric properties are not correlated to the disorder in the sense of distance and bond angles fluctuations in an amorphous network described with a RBM model, but are principally correlated with the occurence of anomalous chemical local configuration in the layer. The creation of these anomalous local chemical configurations may be strongly dependent upon the plasma chemistry and on the plasma technological parameters. It has not been possible to predict the physical and electronic properties of disordered materials from a unique general law.APPROACH AND METHODS SiOxNyHz insulating amorphous thin films (30-400 nm) were prepared by plasma-enhanced chemical vapour deposition (SiH4, N2O and NH3 with and without helium dilution of gases). The preparation parameters were fixed to avoid significant densities of Si-Si bonds. Sets of various SiOxNyHz compositions between Si3N4 and SiO2 were prepared by changing the N2O / (N2O+NH3) gas-flow ratio. The influence of the thickness at layers of a fixed composition was also studied. The refractive index and thickness were obtained from ellipsometry. The mechanical stress and step coverage were investigated. The atomic density profiles were measured by Rutherford backscattering spectrometry and elastic recoil detection. The chemical bonding was studied by infrared spectroscopy. The optical gap was obtained from UV optical absorption. The structural disorder was studied by X-ray grazing incident angle diffraction. The structural defects were observed by dark and light electron-spin resonance. The relative dielectric constant, positive fixed-charge density and interface state density were obtained by high-frequency and quasi-static capacitance-voltage measurements. The breakdown strength and conduction mechanism were obtained from current-voltage measurements. The properties of these amorphous thin films were determined and their dependence on thickness and He dilution explored. The correlation between the network organisation and the electrical properties were proposed. The equilibrium configurations and the electronic and vibrational structures of SiOx and SiNy (respectively) were calculated as a function of oxygen or nitrogen concentration. The effect of hydrogen incorporation on the atomic arrangement and the electronic and vibrational structures were computed. The electronic structure and gap energy calculations were extended to SiOxNy and compared with experimental results. PROGRESS AND RESULTS -For O/O+N increasing from 0 to 1 in SiOxNyHz, the atomic percentages vary as follows: Si is constant around 25%; O increases almost linearly from 0 to 65%; N decreases linearly from 50% to 2%; H is constant at 25% for O/(O+N) <0.4 and decreases for O/(O +N) >0.4; the total atomic density decreases from 1023 cm-3 to 7 x 1022/cm-3. H is mainly present in N-H bonds for O/(O+N) below 0.6 while the Si-H and O-H bond densities remain very low. For O/(O+N) >0.6 H is present in N-H and O-H bonds. The calculated Si-Si bond density is negative, suggesting that if Si-Si bonds exist, their density is very low. -With the same deposition parameters, the macroscopic composition of silicon oxynitrides obtained with the same gas ratios are not modified by the type of reactor, the deposition rate, the layer thickness or the helium dilution. -The important chemical ordering occuring at O/(O+N)=0.4 induces physical property changes at this composition for the type of H incorporation, the stress, the band gap, and the grazing incidence X-ray diffraction. -The stress on c-Si is compressive at all compositions, with a minimum around 0.1 GPa for O/(O+N) around 0.6. -The optical Tauc gap is at the nitride value of 5.4 eV for O/(O+N) <0.4 and then increases up to 9 eV. This result does not depend on the sample thickness. The computed energy gap as a function of O/(O+N) is in agreement with the experimental curve, esp ecially in the change of slope around O/(O+N)=0.4. Calculations established that the absorption steps observed between 7 and 8 eV for 0.7-In addition to the Si dangling bonds always observed in the silicon oxynitrides (Si DB), nitrogen dangling bonds (N DB) are observed for O/(O+N)=0.4 and oxygen NBOH dangling bonds are detected near SiO2. The electrical conduction Poole-Frenkel mechanism through the insulating layer involves the nitrogen dangling bond in the nitrogen rich silicon oxynitride (O/(O+N)<0.4) while the Fowler-Nordheim process involves the silicon dangling bonds in the oxygen-rich silicon oxynitrides (O/(O+N)>0.4). -The positive fixed charges measured at the c-Si interface are correlated with the Si DB point defects in the layers, while the N DB are only involved in the experiments with electric stress leading to strong charge injection processes. -The helium dilution does not change the physical properties at the atomic scale very much and has little effects at the defect scale. It does not improve the electrical properties, as was claimed previously by other authors. -A structure more chemically ordered than the RBM model for the Si-O and Si-N bonds is probable for the medium range silicon oxynitrides. The hydrogen incorporation is also determined by a chemical ordering thermodynamic process instead of by a bond form ation at random. The dangling bond formation is correlated with the appearance of local chemical configuration out of chemical equilibrium in the network. -In the silicon oxynitride, the electric properties are not correlated to the disorder in the sense of distance and bond angles fluctuations in an amorphous network described with a RBM model, but are principally correlated with the occurence of anomalou s chemical local configuration in the layer. The creation of these anomalous local chemical configurations may be strongly dependent upon the plasma chemistry and on the plasma technological parameters. We are not able to predict the physical and electronic properties of disordered materials from a unique general law. The experimental and technological approaches, "trying and measuring", remain at the present time the unavoidable channel. POTENTIAL Understanding the behaviour of amorphous films will enable them to be used in a wide variety of applications in the field of VLSI technology. For example, in the low-temperature fabrication of devices, these films can be used for the intermetallisation or the final passivation layer, and as constituent of memory devices. The silicon oxynitrides may be used in chemical ISFETs sensors as sensitive surface to the pH or as intermediate thin layers on SiO2 allowing the grafting of various ionic sensitive molec ules. In the field of integrated opto-electronic systems or waveguide applications, the silicon oxynitrides are ideal candidates because of their tunable refractive indexes between 1.46 and 2.0. Dziedzina nauki natural scienceschemical sciencesinorganic chemistrynoble gasesnatural sciencesphysical scienceselectromagnetism and electronicsoptoelectronicsnatural sciencesphysical sciencesatomic physicsnatural sciencesphysical sciencesopticsspectroscopyabsorption spectroscopynatural scienceschemical sciencesinorganic chemistrymetalloids Program(-y) FP2-ESPRIT 2 - European strategic programme (EEC) for research and development in information technologies (ESPRIT), 1987-1992 Temat(-y) Data not available Zaproszenie do składania wniosków Data not available System finansowania Data not available Koordynator CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE Wkład UE Brak danych Adres Avenue des Martyrs 25 38042 Grenoble Francja Zobacz na mapie Koszt całkowity Brak danych Uczestnicy (4) Sortuj alfabetycznie Sortuj według wkładu UE Rozwiń wszystko Zwiń wszystko Interuniversitair Mikroelektronica Centrum Belgia Wkład UE Brak danych Adres Kapeldreef 75 3030 Heverlee Zobacz na mapie Koszt całkowity Brak danych UNIVERSITAT POLITECNICA DE MADRID Hiszpania Wkład UE Brak danych Adres RECTORADO, AVENIDA RAMIRO DE MAEZTU, 7 28040 MADRID Zobacz na mapie Koszt całkowity Brak danych UNIVERSITEIT VAN UTRECHT Niderlandy Wkład UE Brak danych Adres PRINCETONPLEINWEG 5, 80000 3508 TA UTRECHT Zobacz na mapie Koszt całkowity Brak danych Université de Montpellier II (Université des Sciences et Techniques du Languedoc) Francja Wkład UE Brak danych Adres Place Eugène Bataillon 34060 Montpellier Zobacz na mapie Koszt całkowity Brak danych
