<p>The invention concerns a method of fabricating a device, comprising the steps of forming a first silicon oxide layer within a first region of said device and a second silicon oxide layer within a second region of said device, implanting doping ions of a first type into said first region, implanting doping ions of a second type into said second region, and etching said first and second regions for a determined duration such that said first silicon oxide layer is removed and at least a part of said second silicon oxide layer remains.</p>
