G Beshkov

Raman and X-ray photoelectron spectroscopy study of carbon nitride thin films

Abstract Carbon nitride thin films were deposited on Si(100) substrates by electron beam evaporation of graphite and simultaneous low energy nitrogen ion bombardment. They were analysed by Raman and X-ray photoelectron spectroscopy. The formed amorphous layers are tetrahedrally bonded and consist of sp3 carbon bonds with one nitrogen atom among its nearest neighbours. Substitution of the tetrahedrally bonded carbon atom by nitrogen leads to decrease of the percentage weight of the nanocrystalline diamond phase and formation of a CNx phase embedded in the amorphous carbon layer. By changing the deposition conditions, redistribution of sp2 and sp3 bonded C–N occurs.

Iron silicide formed in a-Si:Fe thin films by magnetron co-sputtering and ion implantation

Thin films containing iron silicides are prepared by two methods. The first one consists in depositing a-Si:H:Fe thin films by magnetron co-sputtering followed by rapid thermal annealing (RTA). The second one is ion implantation of Fe in a-Si:H thin films and RTA treatment. The samples are characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Rutherford back-scattering (RBS). FTIR spectra show absorption bands typical for β-FeSi 2 at 263, 293, 308, 345 and 425 cm -1 . It is shown that the optimal concentration of Fe in the co-sputtered films to obtain β-FeSi 2 is 35-40% and the optimal RTA temperature is 900°C. XPS spectra show that β-FeSi 2 is formed in as-deposited and annealed co-sputtered a-Si:H:Fe and implanted a-Si:H thin films.

THIN CNX FILMS PREPARED BY VACUUM RAPID THERMAL ANNEALING

Abstract The properties of thin CNx layers prepared by rapid thermal annealing (RTA) are compared with CNxlayers obtained from N2 plasma treatment. Carbon films of 6000 A thickness were deposited by magnetron sputtering system on p-type silicon substrates. The samples were treated in an RTA system in N2 atmosphere at a temperature above 800C. Some of the samples were treated in an N2 plasma. The resulting CNx layers were analyzed by XPS (X-ray photoelectron spectroscopy) technique. The concentration of the incorporated nitrogen and carbon in the layer depths were analyzed by consecutive etching and measurement of the XPS spectra. This showed that maximum depth of incorporated nitrogen atoms in the carbon layer after 800C, 1 min RTA in N2 was about 100 A , while in the N2 plasma treated samples a nitrogen concentration of 6% was observed at 150 A . The electrical resistance of the layers rose with increase of the nitrogen concentration in the layers.

Properties of palladium silicide thin films obtained by vacuum rapid thermal annealing of r.f. sputtered Pd films on Si

Abstract The possibility of obtaining palladium silicide layers by rapid thermal annealing (RTA) has been studied. Palladium layers of 300 and 1000 A thicknesses were deposited by r.f. sputtering on Si substrates. The samples were subjected to RTA at 800, 1000, 1200 and 1400°C for 15 s, 30 s, 1 min and 3 min in vacuum 5×10 −5 Torr. The deposited structure was studied by RHEED. The dependence of the structure and the sheet resistance of the Pd–Si films, as a function of the RTA condition, was established. The sample temperature in the RTA system could be increased from room temperature to the working temperature (800–1400°C) in 2 s. Pd 2 Si was formed after annealing at 1400°C even for short times of 15 s.

X-Ray photoelectron spectroscopy study of phosphorus silicate glasses

Abstract Samples of phosphorus silicate glass (PSG) layers were deposited in a class 100 clean room in two kinds of industrial type reactors: by plasma enhanced chemical vapour deposition (PECVD) and micro pressure chemical vapour deposition (μPCVD) at working temperatures of 380 °C and 430 °C, respectively. After deposition the samples were subjected to rapid thermal annealing (RTA) in a vacuum at 5×10 −3 Pa and temperatures of 800 °C, 1000 °C, 1200 °C and 1400 °C for 15–180 s. X-Ray photoelectron spectroscopy (XPS) investigations show that phosphorous oxides pass through a phase transition and evaporate, while silicon oxides evaporate and decompose. The rate of etching in ‘p’ etcher of μPCVD-PSG layer before annealing is 1023 A min −1 , after RTA at 800 °C for 15 s it is 909 A min −1 , and after annealing for 3 min it is 690 A min −1 . In the case of RTA at 1000, 1200 and 1400 °C for 3 min the etching rates are 660, 469 and 351 A min −1 , respectively, i.e. RTA results in considerable decrease of rate of etching. The same behaviour shows curves related to PSG layers obtained by PECVD. IR spectra show that PO bond vibration at 1320 cm −1 appears at temperatures of annealing T ≥1000 °C and time interval 60–180 s. A correlation between PSG layers characteristics and conditions of RTA is found.

INFLUENCE OF VACUUM RAPID THERMAL ANNEALING ON SOME PROPERTIES OF QUARTZ RESONATORS

Abstract The influence of rapid thermal annealing (RTA) on the parameters of quartz resonators and their amplitude–frequency characteristics has been investigated. The resonators were an AT-cut quartz substrate with Al-electrodes 120 nm thick deposited by electron beam evaporation at 1.10 −5 mbar. The samples were subjected to RTA at the temperature of the heater 700°C, 800°C and 900°C for a time from 15 s to 180 s in vacuum at 5.10 −5 mbar. A correlation between the electrical parameters of the resonators and their amplitude–frequency characteristics from one side and RTA conditions from another side have been established. The conditions under which the quartz resonators parameters were improved have been found.

Properties of µPCVD poly-silicon films after rapid thermal annealing

Polly-Silicon Films obtained by μPCVD were studied with respect to their structural and electrical properties influenced by rapid thermal annealing (RTA) in vacuum. In addition an annealing in H 2 atmosphere at atmospheric pressure was curried out. The structure and the morphology of the films were studied by Reflection High Energy Electron Diffraction (RHEED) technique and Scanning Electron Microscopy (SEM), respectively. An effect of increase of the crystallinity of the poly-Si films was observed as a result of RTA annealing. These observations coincide well with the measured sheet resistance of the layers. It was found that sheet resistance of the as-deposited films is about 5MΩ/□ and it decreases to a value of about 1.6MΩ/□ in dependence on the annealing