V. Kopustinskas

Ion beam synthesis of α-CNx:H films

Hydrogenated amorphous carbon nitride (α-CN x :H) films (100-200 nm) were grown by direct ion beam deposition on Si( 100) substrates. Ion beams have been produced by electrostatic ion sources from C 6 H 14 +H 2 +N 2 gas mixtures. The influence of N 2 / C 6 H 14 +H 2 +N 2 gas ratio (N 2 concentration) on structure and properties of α-CN x :H films was investigated. The increase of N 2 concentration in the gas mixture resulted in decrease of sp 3 bonding and formation of the more graphite-like α-CN x :H films. Growth rate and refractive index of formed α-CN x :H films decreased with increasing N 2 concentration. A slight decrease of wear resistance (<20%) of the formed films with higher nitrogen ratio was also observed.

Replication technology for photonic band gap applications

Abstract Replication technology was applied for photonic structure fabrication in silicon substrate. It was revealed, that thin thermoplastic polymer layers on silicon substrates may be patterned by hot embossing technique for dry etching masking. Ni mold used for plain hot embossing into polymer layers was fabricated by Ni electrochemical deposition on the reference silicon surface structure, which was obtained by direct electron beam (EB) writing and SF 6 /N 2 reactive ion etching (RIE) technique. It is shown that the shape of replicated photonic structures is determined by RIE parameters.

Fabrication of photonic structures by means of interference lithography and reactive ion etching

Abstract In this study, the fabrication of two-dimensional photonic structures by means of interference lithography is discussed. The proposed method provides flexible formation of various configuration two-dimensional interference patterns depending on the number of beams and their interorientation. Mainly, triangular and square lattice configurations are modeled. It is shown that the dimensions of substructure increase with the number of beams superpositioning. Mask fabrication by SF 6 /N 2 reactive ion etching, while transferring the pattern onto silicon substrate is presented.

Imprint lithography of pyramidal photonic pillars using hydrazine etching

Abstract An inexpensive method to produce a pyramidal-type 2D photonic structures in the silicon substrate was proposed. The method is based on the combination of imprint lithography and wet Si 〈1 0 0〉 etching in water solution of hydrazine, which etches 〈1 1 1〉 faces much more slowly than others. Thermally grown SiO 2 mask for the hydrazine etching was used, because single Al mask cannot be well bonded to the substrate and tends to peel during the etching. It was revealed that transmittance in the infrared spectrum region of the patterned silicon decreases by about five times compared with that of flat silicon substrate and this decrease is almost independent of the angle of the incident beam. In the infrared region, decrease of transmittance of the patterned samples is directly proportional to the wave number. The shape of formed pyramids has strong influence on the transmittance. Decrease of the transmittance is much more rapid and larger in the case of sharpless pillars.

Optical properties of the undoped and SiOx doped DLC films

In present study DLC films were deposited by direct ion beam deposition. Hexamethyldisiloxane vapor and hydrogen gas mixture, mixture of the hexamethyldisiloxane with acetylene as well as acetylene gas alone has been used as a source of the hydrocarbons. Optical properties of the synthesized films were investigated by spectroscopic ellipsometry. Structure of the DLC films has been studied by means of the Raman spectroscopy. Effects of the technological deposition parameters such as composition of the gas precursors, ion beam energy, ion beam current density were considered.

Electrical properties of the diamond like carbon films irradiated with high energy photons

SiOx—containing amorphous diamond like carbon (DLC) is very attractive material for a number of practical applications. DLC films are possible candidates for the formation of passive layers in electronic devices and are used as protective coatings. Both applications are interesting for the construction of medical radiation detectors. Radiation induced structural changes and electrical properties of DLC: SiOx films (undoped and co-doped) synthesized at room temperature by means of direct ion beam deposition method were investigated after their irradiation with high energy (Emax = 15 MeV) X-ray photons. It was found that transparency of the irradiated DLC films was not changed significantly, as compared to initial samples, stating only small increase of the optical band gap in DLC films. However radiation induced changes were dependent on co-doping and film deposition conditions which were responsible for the sp3/sp2 ratio and hydrogen content in the investigated films. Analysis of U-I characteristics showed decreasing tendency of the leakage current in the range 0–20 V and especially high dependency of breakdown voltage on the deposited contact area in irradiated films as compared to initial samples. Possible mechanism of radiation induced changes in irradiated DLC films is discussed on the basis of the results of Raman and Infrared spectroscopy.

alpha-C:H films for photonic structure fabrication

(alpha) -C:H films were applied to fabricate photonic band gap (PBG) structures in the silicon substrate by SF6N2-based reactive ion etching (RIE). The influence of RIE parameters on (alpha) C:H films structure and etching rate was investigated int his study. It is shown that RIE rate for (alpha) -C:H films changes from 26 nm/min to 38 nm/min with the integrated intensity ratios ID/IG varied from 0.65 to 1.1. It is evident that increase in etching rate is determined by increasing quantity of sp2 bonding in the synthesized (alpha) -C:H films. RIE does not change structure of the (alpha) -C:H masking films. However, non- uniform character of RIE takes place due to the non- homogeneous graphite clusters in (alpha) -C:H masking films. However, non-uniform character of RIE takes place due to the non-homogeneous graphite clusters in (alpha) -C:H masking films. By changing parameters of silicon etching, such as RF power density, pressure and negative bias voltage, anisotropy was varied in wide range and microstructures of different shape were obtained.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.