Yves Nissim

Operation of nonlinear GaAs/AlGaAs multiple quantum well microresonators fabricated using alloy-mixing techniques

We report for the first time the fabrication and the operation of GaAs/AlGaAs multiple quantum well nonlinear microresonators employing defect‐induced alloy‐mixing techniques. A uniform array of 5‐μm square microresonators shows a hysteresis behavior in the reflection mode and in a quasi‐continuous regime. We demonstrate that the pixellation indeed improves the nonlinear properties of the structures.

Surface reactions of silane with oxidized InP and their application to the improvement of chemical vapor deposition grown, InP-based metal-insulator-semiconductor devices

The first stage of chemical vapor deposition of SiO2 from SiH4 and O2 on InP has been investigated. SiH4 is shown to interact only with an oxidized InP surface. It plays the part of an interface deoxidizing agent, restoring the covalent bonding of surface InP atoms. Oxygen originally bonded to InP becomes bonded to the silicon deposit in silica‐like bonds. This phenomenon has been used as an in situ surface cleaning step in the processing of metal‐insulator‐semiconductor InP structures. It leads to a strong decrease of the hysteresis in capacitance‐voltage curves, demonstrating improvement of the interface properties.

Tunable UV-flash krypton lamp array useful for large area deposition and in situ UV annealing of Si-based dielectrics

Abstract A low pressure VUV flashlamp at 100 Torr has been developed as a tool for ‘cold’ UV CVD and processing. The current density is related in a tunable fashion to the VUV spectral distribution (160–260 nm) up to 20 Hz. A high brightness (3400 W/Hz cm2 sr) Kr flashtube was shown to be a superior VUV source to Xe and Ar for Si-based dielectrics. The VUV efficiency of the Kr flashlamp, operated at up to 10 kA/cm2, is relatively high, up to 10%, in the spectral region. By setting four efficient Kr flashtubes, in a separate cavity, a lamp source, together with the UV CVD system characteristics, are shown useful to overall ‘cold’ processing, with focus on uniform large area, cleaning, and in situ deposition, up to 3% for 3″. The deposition rates are conveniently high, ∼100 A/min at 350°C, but well controllable to obtain several dielectric thin films on III–V materials: silicon dioxide, nitridised silicon dioxide, and silicon nitride. Device quality electrical and optical features for III–V technology are demonstrated: a zero-hysteresis MIS-InP and as a proof of the passivation of GaAs surface, the MIS-GaAs capacitor.

Bulk and surface properties of RTCVD Si3N4 films for optical device applications

Abstract Rapid thermal chemical vapour deposition is proposed to obtain optical-quality silicon nitride films on III–V semiconductors. The films have been obtained on InP at high temperature with a very high growth rate. Structural and morphological properties of nearly stoichiometric silicon nitride are presented. Nuclear reaction analysis (NRA), Rutherford backscattering (RBS) and Fourier transform infrared spectroscopy showed that the films are dense and have a uniform thickness. Scanning electron microscopy (SEM) revealed that the surface morphology of the silicon nitride films is dependent on the thickness of the films. Atomic force microscopy (AFM) allowed us to image the dielectric surface and to obtain roughness values as a function of the experimental conditions of deposition. Refractive indices measured at 6328 A are linearly dependent on the film thickness. We show that the refractive index in this case is also tightly connected to the surface morphology of the deposited thin film.

Evidence for a transitory composition pattern in the early stages of the photochemical deposition of silica films on semiconductors

We have studied the early stages of the photodeposition of SiO2 on semiconductors from silane–oxygen gaseous mixtures under UV irradiation. For film thicknesses below 100 A, the films exhibit a specific oxygen‐deficient composition which become stoichiometric if deposition lasts longer, producing SiO2 films with a homogeneous composition throughout the whole dielectric layer. It is shown that the transitory early deposition regime is structurally sensitive to the nature of the substrate. Cathodoluminescence is used to show that the surface carrier recombination properties are altered mostly during this singular early stage of photodeposition.

Light-assisted deposition of silicon-based dielectrics for optical interconnection in optoelectronics☆

Abstract The structural quality of rapid thermal chemical vapour deposited dielectric films have been utilized to fabricate optical waveguides at 1.5 μm. The guides composed of SiO x N y guiding layer sandwiched between two SiO 2 layers. A precise model has been utilized to define the indexes of refraction and thicknesses of the different layers. Special care has been made in the fabrication process to define the entrance and exit facets of the guide. A resulting loss of 1.5 dB/cm has been measured in this structure. This result is among the lowest losses reported on as-deposited dielectric guides.

Integration of plasma cleaning and light-assisted CVD for the passivation of III-V semiconductor surfaces

Abstract Passivation of III-V semiconductor surfaces and especially the GaAs surface has been studied for over two decades without significant breakthrought. However III-V device performances are still often limited by surface properties. In particular field effect behaviour in GaAs has been impossible to obtain due to the Fermi level pinning at the surface of this material. This paper presents an integrated sequence of low thermal budget processes to provide contamination control at the GaAs surface leading to very promising field effect on GaAs. In-situ surface cleaning using a Distributed Electron Cyclotron Resonance Microwave plasma (DECR MMP) has been integrated with a thin dielectric film deposition facility using light assisted CVD technics. Photoluminescence results carried out on GaAs surfaces have demonstrated that exposure to a hydrogen plasma induces lower recombination rates on these surfaces. Bulk diffusion of hydrogen during this process can be controlled and eliminated using an integrated Rapid Thermal Annealing (RTA). Finally, in-situ encapsulation by a dielectric allows one to stabilize the electronic properties of the surface for passivation applications. A silicon nitride film deposited by a direct UV photolysis deposition process has been developed for this study and is presented here.