InGaAs-OI Substrate Fabrication on a 300 mm Wafer
In this work, we demonstrate for the first time a 300-mm indium–gallium–arsenic (InGaAs) wafer on insulator (InGaAs-OI) substrates by splitting in an InP sacrificial layer. A 30-nm-thick InGaAs layer was successfully transferred using low temperature direct wafer bonding (DWB) and Smart CutTM technology. Three key process steps of the integration were therefore specifically developed and optimized. The first one was the epitaxial growing process, designed to reduce the surface roughness of the InGaAs film. Second, direct wafer bonding conditions were investigated and optimized to achieve non-defective bonding up to 600 °C. Finally, we adapted the splitting condition to detach the InGaAs layer according to epitaxial stack specifications. The paper presents the overall process flow that achieved InGaAs-OI, the required optimization, and the associated characterizations, namely atomic force microscopy (AFM), scanning acoustic microscopy (SAM), and HR-XRD, to insure the crystalline quality of the post transferred layer.
300 mm InGaAs-on-insulator substrates fabricated using direct wafer bonding and the Smart Cut™ technology
This paper reports the first demonstration of 300 mm In0.53Ga0.47As-on-insulator (InGaAs-OI) substrates. The use of direct wafer bonding and the Smart Cut™ technology lead to the transfer of high quality InGaAs layer on large Si wafer size (300 mm) at low effective cost, taking into account the reclaim of the III–V on Si donor substrate. The optimization of the three key building blocks of this technology is detailed. (1) The III–V epitaxial growth on 300 mm Si wafers has been optimized to decrease the defect density. (2) For the first time, hydrogen-induced thermal splitting is made inside the indium phosphide (InP) epitaxial layer and a wide implantation condition ranges is observed on the contrary to bulk InP. (3) Finally a specific direct wafer bonding with alumina oxide has been chosen to avoid outgas diffusion at the alumina oxide/III–V compound interface.
Effect of superficial gas velocity on the particle temperature distribution in a fluidized bed with heat production
The heat transfer behavior of particles and gas in an olefin polymerization fluidized bed was numerically analyzed using an in-house developed 3-D computational fluid dynamics discrete element model (CFD-DEM). First the implementation of the model was verified by comparing simulation results with analytical results. A constant volumetric heat production rate was implemented in the particle energy equation to mimic the heat production due to the polymerization reaction. It was found that the probability density function (PDF) of the particle temperature becomes more homogeneous with increasing superficial gas velocity. Furthermore, instantaneous snapshots of the thermal driving force (the difference between the single particle temperature and bed-average gas temperature, Tp− ) for different heat production rates provide detailed insight in the particle temperature distribution inside the fluidized bed. The time- and bed-averaged particle convective heat transfer coefficient, which was calculated by Gunn׳s correlation, was found to be independent of the superficial gas velocity. This is explained by the fact that the relative velocity of gas and particles in the emulsion phase, where most of the particles and gas interact, is hardly influenced when increasing the gas superficial velocity. From the spatial distribution of Nusselt number, it becomes apparent that the high heat transfer regions are found in the wake of rising bubbles, whereas low heat transfer rates are found in the clouds of the bubbles.