Soitec

S.o.i.tec Silicon on Insulator Technologies

Khalid Radouane

Ludovic Ecarnot

Patrick Reynaud

Cecile Aulnette

Alessandro Baldaro

A method to thin an initial silicon-on-insulator substrate that has a layer of silicon oxide buried between a silicon carrier substrate and a silicon surface layer. This method is noteworthy in that it includes conducting a thermal oxidation treatment of the initial substrate to cause oxidation of part of the silicon surface layer and form a thermal oxide thereon; conducting a first cycle of etching followed by cleaning of the silicon surface layer after the thermal oxidation treatment, wherein the etching of the first cycle is conducted so as to fully remove the thermal oxide from the silicon surface layer to thin it and lift off all unstable parts of the initial substrate at edges thereof to form a thinned substrate; conducting, after the first cycle, a second cycle of etching followed by cleaning of the silicon surface layer, wherein the etching of the second cycle is conducted to remove from the surface of the thinned substrate, polluting particles formed during the first etching cycle and that have deposited thereupon, in order to obtain a final SOI substrate having a thinned surface layer that forms an active layer for the substrate.

Method to thin a silicon-on-insulator substrate

The present invention relates to a method of treating wafers comprising at least one surface layer of silicon-germanium (SiGe) and a layer of strained silicon (sSi) in contact with the SiGe layer, the sSi layer being exposed by etching of the SiGe layer, the method comprising the steps of: The present invention relates to a wafer comprising at least one surface layer of strained silicon (sSi), the at least one surface layer of sSi having a thickness of at least 5 nm and at most 100 &#x3bc;m and having at most 200 defects per wafer.

Process for preparing cleaned surfaces of strained silicon

The invention relates to a method for recycling a substrate with a step-like residue in a first region of its surface, in particular along the edge of the substrate, which protrudes with respect to the surface of a remaining second region of the substrate, and wherein the first region comprises a modified zone, in particular an ion implanted zone, essentially in a plane corresponding to the plane of the surface of the remaining second region of the substrate and/or chamfered towards the edge of the substrate. To prevent the negative impact of contaminants in subsequent laminated wafer fabricating processes, the recycling method comprises a material removal step which is carried out such that the surface of the substrate in the first region is lying lower than the level of the modified zone before the material removal. The invention also relates to a laminated wafer fabricating method using the recycled substrate and to a recycled substrate in which the surface of a first region lies lower than the surface of the second region.

Methods for recycling substrates and fabricating laminated wafers

A process for reducing or suppressing the appearance of watermarks in a hydrophobic surface of a semiconductor substrate prepared as a base substrate for epitaxial growth. The process includes cleaning the hydrophobic surface of the semiconductor substrate with an aqueous solution containing hydrofluoric acid (HF) and an additional acid having a pKa of less than 3, preferably hydrochloric acid (HCl), wherein the additional acid is present in the solution at a concentration by weight that is less than that of the HF; and final rinsing the cleaned hydrophobic surface of the semiconductor substrate with deionised water while subjecting the hydrophobic surface of the semiconductor substrate to megasonic waves for a time sufficient to reduce or suppress watermarks that could otherwise occur on the hydrophobic surface if the megasonic waves were not applied.

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Carrieres sur Seine, France

Khalid Radouane