J. Garrido

Compositional and electrical properties of ECR-CVD silicon oxynitrides

Silicon oxynitride layers were deposited by electron cyclotron resonance (ECR) plasma enhanced chemical vapour deposition (PECVD). Oxygen, nitrogen and 5% argon diluted silane were used as precursors. The gas composition in the plasma was varied over a wide range to get compositions from pure to layers with around 20% O content. Large flow ratios are required to get significant N concentrations in the deposited layers. Pure layers could only be obtained when flow was completely suppressed. The infrared spectra of ECR are very similar to those of thermally grown oxides, but significant differences were found between the ECR and the high-temperature CVD spectra. MOS devices fabricated with these layers show that the interface state density increases from about to when the layer composition changes from pure to pure .

Passivation, structural modification, and etching of amorphous silicon in hydrogen plasmas

Atomic hydrogen from plasma discharges dissolves in silicon previously amorphized by ion implantation (aSi) in the form of Si–H bonds, giving rise to infrared (IR) absorption at ∼1990 cm−1 and causing partial activation of implanted dopants. Passivation of aSi does not affect the rate at which the material subsequently undergoes solid phase epitaxy. Exposure giving rise to [H]>6 at. % causes the appearance of an additional IR absorption band at ∼2080 cm−1 and coloration of the layer. Despite annealing, the Si–H defects, normal solid phase epitaxy does not occur during subsequent heat treatment. The structural modification by H-plasma exposure coincides with etching of the layer. The observations can be understood in terms of void formation in aSi resulting from the clustering of Si–H.

Amorphous SiC layers deposited by electron cyclotron resonance plasma: spectroscopic ellipsometric measurements

Abstract Hydrogenated silicon carbide was deposited in electron cyclotron resonance plasma. Pure methane and silane diluted with 5% argon were used as gas precursors. The compositions of the layers depends on the CH 4 /SiH 4 flow ratio used for deposition. For flow ratios equal to or larger than 2, around 80% of the layer consists of Si-C bonds, the rest being Si-H n and C-H n bonds. The amorphous silicon content increases as the flow ratio decreases, as indicated from ellipsometry and infrared measurements.

Electrical properties of electron cyclotron resonance plasma-deposited silicon dioxide: effect of the oxygen to silane flow ratio

Silicon dioxide layers have been deposited at from electron cyclotron resonance plasma using pure oxygen and argon-diluted silane. The sign of the oxide charge depends on the flow ratio and also on the post-deposition processing. In the post-metallization annealed layers, net negative charge densities as low as have been obtained in the best conditions. Most of the charge seems to be trapped at oxide centres and the measured mobile charge is negligible. Post-oxidation treatments did not anneal out the oxide traps but released additional positive charge in the oxide.

Rapid solid phase crystallization of nanocrystalline silicon deposited by electron cyclotron plasma chemical vapor deposition

Nanocrystalline silicon films were deposited in an electron cyclotron resonance plasma of Ar+H2+SiH4 on (100) and (111) oriented Si substrates without external heating. Before deposition, the substrates were cleaned in situ in an Ar+H2 plasma. This cleaning process caused surface roughness particularly on (100) substrates. Apparently, the excessive roughness of the interface with (100) Si surface prevented complete crystallization of the subsequently deposited films. In contrast, rapid solid phase crystallization of the films deposited on (111) surfaces occurred at around 1000 °C.

Regrowth-process study of amorphous BF2+ ion-implanted silicon layers through spectroscopic ellipsometry

The recrystallization kinetics of BF2+ ion-implanted silicon has been studied by means of spectroscopic ellipsometry. It has been found that the dielectric constant of the implanted layers depends on the energy, dose and ion-beam current. The activation energy of the regrowth process increases with ion peak concentration becoming saturated for the largest implanted doses. In the largest-dose samples implanted at low current a significant decrease of the regrowth rate was detected when the recrystallization front crosses the peak of the impurity distribution.

Scanning electron beam annealing of sputter-deposited titanium on silicon

Abstract Ti thin films sputter-deposited on single crystal Si wafers were annealed by using a scanning electron beam source. The resulting titanium silicides have been characterized by RBS and X-ray diffraction techniques. The experimental results show that the initial Ti layer thickness, in the studied range of 50 to 500 nm, does not affect the amount of formed silicide. RBS measurements are not enough to deduce the silicide composition due to the lack of well defined interfaces. X-ray measurements indicate the presence of only a single silicide phase, Ti5Si4. These results indicate that the interfaces in the structure Ti-silicide-Si, resulting from the e-beam treatment, are corrugated.

Electronic defect levels in continuous wave laser annealed silicon metal oxide semiconductor devices

The effect of laser treatment on the bulk and interface states of the Si‐SiO2 structure has been investigated. The annealing was performed prior to the gate metallization using a continuous wave Ar+ laser. For low laser powers the interface state density seems to decrease slightly in comparison with untreated samples. However, for the highest irradiating laser powers a new bulk level at 0.41 eV above the valence band with concentrations up to 1015 cm−3 arises probably due to the electrical activation of the oxygen diluted in the Czochralski silicon. Later postmetallization annealings reduce the interface state density to values in the 1010 cm−2 eV−1 range but leave the concentration of the 0.41‐eV center nearly unchanged.

Temperature evolution during scanning electron beam processing of silicon

Temperature profile evolutions produced by a scanning electron beam in crystalline silicon have been numerically calculated using a two-dimensional finite-element scheme. The temperature dependence of the different silicon properties as well as the electron penetration effects have been taken into account. Numerical calculations carried out at different conditions have been compared with experimental melting-threshold measurements using an electron beam with a Gaussian power density distribution. The good agreement between numerical calculations and experimental results proves the validity of the two-dimensional approach.

Hydrogen Incorporation and Crystallization of Nanocrystalline Silicon Deposited by Electron Cyclotron Resonance Plasmas

The archival version of this work was published in J. Electrochem. Soc.146.5, (1999): 1966-1970.