jean-louis Lievin

• PhD
• CSO & CEO at ideXlab

Combine endogenous and exogenous ideas through internal or external paths to market to develop advances in services, products or processes are the main objectives of organizations when they implement an open innovation (OI) strategy. Since Chesbrough’s first description, the number of companies who have adopted OI has experienced a tremendous growt...

Buried heterostructure lasers fabricated using reactive ion etching for stripe definition and gas source molecular beam epitaxy for blocking layer regrowth are presented for the first time. The structure design includes, in particular, a nonselective epitaxial regrowth step as well as a III‐V material lift‐off. Preliminary results show continuous w...

Buried heterostructure lasers fabricated using a three‐step gas source molecular beam epitaxy (GSMBE) process are presented for the first time. We propose a new structure design compatible with nonselective regrowth for the blocking layers, therefore avoiding the use of a dielectric mask. The structure is terminated by a second overgrowth after a m...

The growth of high quality InP and In 1-xGa xAs yP 1-y by gas source molecular beam epitaxy is reported. 77 K mobilities up to 112,000 cm 2/Vctdots for high purity InP have been measured. Fe-doped semi-insulating InP has been grown using an iron effusion dell, and resistivities as high as 10 9 Ω cm have been obtained. Selective epitaxy of InP on Si...

Chemical beam epitaxy (CBE) is demonstrated here to be a suitable technique for the planarization of etched structures by selective overgrowth of InP layers. We present the fabrication of planar buried heterostructure laser diodes (PBH‐LDs) with a separate confinement multiquantum well active layer grown by gas source molecular beam epitaxy and p‐n...

An electro-optic polarisation converter with 1.1 degrees /Vmm rotation efficiency grown on

Measurements of threshold current density and external efficiency on broad-area laser-waveguide structure have led to the determination of the optical loss and differential loss d alpha /dN approximately=1.1-2.3 *10^-17 cm² at lambda =1.53 mu m in a lambda _g=1.30 mu m GaInAsP layer. This measurement will be useful fo...

GaInAs/GaInAsP multi-quantum-well structures emitting at 1.55 mu m have been realised by gas source molecular beam epitaxy (GSMBE) over a large range of growth temperature. Threshold current densities as low as 0.81 kA/cm² have been obtained. The first BH lasers fabricated by GSMBE from these heterostructures exhibit low threshold curren...

The growth by molecular‐beam epitaxy of high‐quality epitaxial layers of GaAs, AlGaAs, and InGaAs on GaAs substrates oriented normal to the [111] direction is reported. The (111)B surface of GaAs is found, in contrast to the (001) surface, to be extremely fragile after the desorption of its oxide. Surface roughening occurs within seconds of oxide d...

In this paper, we present the molecular beam epitaxy of very high p-type doping levels into GaAs using beryllium as a dopant. Very low resistivity, multilayer-compatible material is achieved with doping levels as high as 2 × 1020cm-3. We study the beryllium incorporation during growth, and discuss, based on experimental results, how such layers can...

This letter reports the first reflection high‐energy electron diffraction intensity oscillation study of strained, pseudomorphic In 1-x Ga x As and In 1-y Al y As grown by molecular beam epitaxy on InP substrates. Strain‐induced effects are studied over a broad range (up to 3%) of positive and negative mismatch. During mismatched growth, an abnorma...

We report the first operating heterojunction bipolar transistor with a base made of a GaAs/Ga1−xAlxAs superlattice (superlattice bipolar transistor or SBT device). The MBE growth conditions of such structures are described and the importance of a careful X-ray characterization of the superlattice parameters is pointed out. A drastic variation of th...

The development of optical transmission calls for sensitive and fast optoelectic transducers. With the advent of optical local area networks, hybrid transducers may no longer be appropriate, and monolithic emitters and receivers will be preferred. In this paper, we report on the first monolithic photoreceiver implemented with GaAs-GaAIAs bipolar de...

We report the first operating bipolar transistor built with an AlGaAs/GaAs superlattice base. High current gain is measured with a suitable design of the bipolar transistor structure. Experimental results are in good agreement with a Bloch to hopping transition which is very sensitive to the AlGaAs barrier thickness. This interpretation is supporte...

We report an investigation of two effects related to the low quality of MBE Ga1−xAlxAs layers and of the Ga1−xAlxAs/GaAxAs heteroiinterface (resulting from the growth of Ga1−xAlxAs on top of GaAs), as compared to the GaAs/Ga1−xAlxAs one. First, a surface roughness is observed for Ga1−xAlxAs layers grown under specific conditions, and notnot for the...

We report the first heterojunction bipolar transistor (HBT) with base doping level as high as 2 × 10²⁰cm^-3. The device is grown by molecular beam epitaxy (MBE) with growth conditions adjusted to keep perfect surface morphology and to avoid dopant diffusion even at ultra-high doping levels. Maximum dc current gain of 10 is obse...

Ce travail présente l’élaboration en épitaxie par jets moléculaires d’hétérostructures GaAlAs-GaAs pour transistor et circuit intégré bipolaire. La caractérisation du matériau et des hétérointerfaces est réalisée notamment en par cathodo-luminescence, mesures de durée de vie, et photoluminescence de puits quantiques. De très forts dopages de type p...

We present low‐temperature photoluminescence studies of nominally undoped GaAs quantum wells in which weak acceptor‐related emissions can be observed. We investigate the influence of different sequences of prelayers, in which the number and the aluminum concentration of the layers are varied, on the impurity concentration in the quantum well, and s...

We have investigated the photoluminescence excitation spectroscopy of GaAs-Ga1-xAlxAs separate confinement heterostructures consisting of a narrow GaAs quantum well embedded in a larger Ga1-xAlxAs one. Quantization of the energy in the ``upper'' large well is observed for thicknesses smaller than 750 A&#778. The peculiar structure configuration all...

We have optimized the growth conditions of (Ga,Al)As/GaAs heterojunction bipolar phototransistors (HPT's) using MOCVD or MBE techniques. Devices with current-gains higher than 3000 and low input capacitances have been obtained using a fabrication process suitable for IC's. A photoreceiver has been designed with predicted performances of -39.5 dBm a...

I–V modelling of heterojunctions taking into account the heterointerface parameters is used to establish an analytical model of collector/emitter offset voltage in Heterojunction Bipolar Transistors. It is shown that careful design of Emitter Base (E-B) and Collector Base (C-B) interfaces can eliminate this problem. Comparisons with experimental re...

P-type doping levels up to 2×1020 at cm¿3 in GaAs are presented using molecular beam epitaxy and beryllium as acceptor impurity. The epilayers present a perfect surface morphology and Be is not found to diffuse into the substrate, which permits the incorporation of such films into multilayer structures for device applications.

The design and fabrication technology of a monolithic integrated transimpedance photoreceiver preamplifier using an HPT (Heterojunction bipolar phototransistor) and HBT's (Heterojunction bipolar transistors) are discussed in this paper. The receiver has a predicted sensitivity of - 39,5 dBm at 140 Mbit/s and a bandwidth of 300 MHz without equalizat...