XIV International Conference on "Gettering and Defect Engineering in Semiconductor Technology

The technology for thin Ge layer transfer by hydrogen ion-cut process is characterised in this work. Experiments were carried out to determine suitable hydrogen ion implantation doses in germanium for the low temperature ion cut process by examining the formation of blisters on implanted samples. Raman and Spreading Resistance Profiling (SRP) have been used to analyse defects in germanium caused by hydrogen implants. Bevelling has been used to facilitate probing beyond the laser penetration depth. Results of Raman mapping along the projection area reveal that after post implant annealing at 400 oC, some crystal damage remains, while at 600 oC, the crystal damage has been repaired. SRP shows that some amount of hydrogen acceptor states (~1I1016 acceptors/cm2) remain after 600 oC. These are thought to be vacancy-related point defect clusters

Surface states in optical spectra of two-dimensional photonic crystals with various surface terminations

Reflection and transmission spectra of two-dimensional photonic crystal slabs, fabricated by photoelectrochemical etching of deep macropores and trenches in Si, are investigated theoretically and experimentally. It is shown that the presence of an unstructured silicon interfacial layer between the air and the photonic crystal structure can give rise to surface (Tamm) states within the TE and TM photonic stop bands. In the presence of roughness of inner surfaces of air pores, the surface states show up as dips within the stop bands in the reflection spectrum. The calculated electromagnetic near-field distribution demonstrates the vortices between the upper pores at the frequency of the surface mode. The experimental reflection and transmission spectra are in a good agreement with theoretical calculations performed by the Fourier modal method in the scattering matrix form

Reversal and pinning of Curie point transformations in thin film piezoelectrics

The Curie point for a rhombohedral piezoelectric thin film was established by in situ micro-Raman spectroscopy. The hysteresis in phase reversal and specific thermal conditions for disrupting such reversal were determined

Design of One-dimensional Photonic Crystals Using Combination of Band Diagram and Photonic Gap Map Approaches

peer-reviewedThe design of one-dimensional photonic crystals and the analysis of their optical properties have been performed using band diagram and forbidden gap map methods. It has been shown that the latter method is more useful for practical applications since (i) it can be applied for any number of periods and (ii) it is more suitable for the selection of a filling fraction in a wide range of values using a single graphical presentation. Three different types of photonic crystals with small, medium, and high optical contrast were modeled using both methods. The features of the omnidirectional band gap formation for photonic crystals with small optical contrast and low number of periods have been explained. The formation of a one-dimensional photonic structure with limited number of periods and omnidirectional band gap close to that for an infinite periodic structure has been discussed

Opto-Ireland 2005: Optoelectronics, Photonic Devices, and Optical Networks

The orientation of nematic liquid crystal (LC) E7 on the surface of (111) silicon wafers and in the channels of grooved silicon structure has been investigated. Grooved Si is a periodical structure obtained by wet anisotropic etching of deep and narrow grooves in (110) Si using an alkaline solution. This structure can serve as a one-dimensional (1D) photonic crystal. Composite structures obtained from grooved Si infiltrated by LC are promising candidates for electro-optic application. LC E7 was infiltrated into the channels of grooved Si and into the bulk Si cells. IR spectroscopy and capacitance-voltage characteristics under DC electric field were applied to investigate LC orientation. It is shown that the E7 liquid crystal in grooved silicon exhibits a weak planar orientation with respect to the silicon walls

Design, fabrication and optical characterization of Fabry-Pérot tunable resonator based on microstructured Si and liquid crystal

The results of a simulation of the optical properties of a silicon Fabry-Perot resonator (with liquid crystal filler in the cavity), operated on the shift of the interference bands in the infrared range are presented. The possibility of tuning the reflection coefficient from 0 to 0.95 (or transmission coefficient from 1 to 0.05) by changing the refractive index by 0.1 in the cavity and using the stop-bands and resonance peaks of high order is demonstrated. The prototype Fabry-Perot resonators were fabricated by dry and wet etching of (100)Si and (110)Si. Some of the resonators were fabricated on a silicon-on-insulator platform. A superposition of transmission peaks with reflection maxima, predicted from calculations, was confirmed experimentally, using infrared microspectroscopy, with a temperature variation from 20 oC to 65 oC and an applied electric field from 0V to 10V

Multi-channel, Si-Liquid Crystal Filter, with Fine Tuning Capability of Individual Channels for Compensation of Fabrication Tolerances

In this study, a technique for the optimization of the optical characteristics of multi-channel filters after fabrication is proposed. The multi-channel filter under consideration is based on a Si photonic crystal (PhC), tunable liquid crystal and opto-fluidic technologies. By filling air grooves in the one-dimensional, Si-Air PhC with a nematic liquid crystal, an efficiently coupled multi-channel filter can be realised in which a wide stop band is used for channel separation over a wide frequency range. By selectively tuning the refractive index in various coupled cavities, continuous individual tuning of the central channel (or edge channels) up to 25% of the total channel spacing is demonstrated. To our knowledge, this is the first report on the electro-optical solution for the compensation of fabrication tolerances in an integrated platform

Determination of substitutional carbon content in rapid thermal chemical vapour deposited Si1-x-yGexCy on Si (1 0 0) using Raman spectroscopy

The effect of carbon content on strain compensation in rapid thermal chemical vapour deposited Si1-x-yGexCy films was investigated using Raman spectroscopy as x varies from 10% to 16% and y varies from 0% to 1.8%. The dependence of the Raman intensities of the carbon local modes and the Si-Si modes versus carbon content was analysed. A linear dependence has been revealed for the integrated and peak intensities of these vibrational modes versus C content for samples with x ? 16%. This shows that Raman scattering measurements can be utilised for determination of the substitutional carbon content in SiGeC layers with a Ge content up to 16%