An optoelectronic circuit with a light source, an optical waveguide and a sensor all on silicon: Results and analysis of a novel system

AbstractA full analysis of an optoelectronic circuit on silicon composed by a light emitter, an optical waveguide and a photodetector is achieved. The light emitter is based on silicon rich oxide multilayers. The multilayer structure exhibits an electroluminescence spectra from 400nm to 800nm. Light emitter and optical waveguide are located next to each other in a novel topology that allows the direct impact of the photons to the depletion layer of the sensor, increasing the efficiency. An optical rib-type waveguide and multi-modal, using Si3N4 and SiO2 as core and cladding materials, is considered to propagate the light from the light emitter to the sensor. Analysis of the waveguide reveals that the optimal height is 1.25µm, when a width of 5µm and a fractional height of 0.8 are used. A relative transmittance of the optical waveguide shows that the propagated light maintains the wide spectrum. A planar diode is used as photodetector. The proposal-integrated structure shows that light impinges directly on the depleted zone, improving detection and performance of the diode. Finally, a description of the novel optoelectronic circuit is addressed

MIS Transistor with Integrated Waveguide for Electrophotonics and the Effect of Channel Length in Light Detection

In this work, we study the optical response of MOS-like transistors with a Si3N4 integrated waveguide which serves also as the dielectric of the gate, and P-type substrate with 1´1012 cm-3 acceptor concentration and different channel length. Simulation results show the possibility to integrate this kind of MIS transistor as detectors in an electrophotonic circuit compatible with CMOS fabrication process and obtaining electrical gain for low power light signals (below 400 nW)

Characterization of Silicon Rich Oxides with Tunable Optical Band Gap on Sapphire Substrates by Photoluminescence, UV/Vis and Raman Spectroscopy

A detailed analysis of the optical properties of silicon rich oxides (SRO) thin films and the factors that influence them is presented. SRO films with different Si content were synthesized via LPCVD (low pressure chemical vapor deposition) on sapphire substrates. Photoluminescence (PL), UV/Vis and Raman spectroscopy were used to characterize the samples. An intense emission in blue region was found. An interesting fact is that the optical band gap correlates linearly with the reactants ratio, which allows the tuning of the band gap. The influence of parameters such as substrate, Si content, annealing temperature and annealing time on the optical properties are discussed and the possible mechanisms of the photoluminescence are compared with our experimental data.523212218Deutsche Forschungs GemeinschaftCONACy

Photoelectric Properties of MOS-like Structures with Twofold SRO Films

AbstractThe optical properties of silicon rich oxide (SRO) have been deeply studied because, between other reasons, they emit an intense photoluminescence (PL) from visible to the near infrared range when excited with UV light. MOS-like structures with SRO film as the active layer have shown an enhanced conductivity under different illumination conditions. In this paper, MOS-like structures with double SRO layer were fabricated in order to have a barrier to isolate the silicon substrate from the active SRO layer. Results show that all structures have a higher current when light shines on them than that obtained under dark conditions. A possible application of this photo-effect can be used to increase the response of photodetectors and silicon solar cells

Silicon-Rich Oxide Obtained by Low-Pressure Chemical Vapor Deposition to Develop Silicon Light Sources

Off stoichiometric silicon oxide, also known as silicon-rich oxide (SRO), is a light-emitting material that is compatible with silicon technology; therefore, it is a good candidate to be used as a light source in all-silicon optoelectronic circuits. The SRO obtained by low-pressure chemical vapor deposition (LPCVD) has shown the best luminescent properties compared to other techniques. In spite of LPCVD being a simple technique, it is not a simple task to obtain SRO with exact silicon excess in a reliable and repetitive way. In this work, the expertise obtained in our group to obtain SRO by LPCVD with precise variation is presented. Also, the characteristics of this SRO obtained in our group are revised and discussed. It is demonstrated that LPCVD is an excellent technique to obtain single layers and multilayers of nanometric single layers with good characteristics