Forming Si nanocrystals on insulator by wet anisotropic etching

•A method to fabricate Si nanocrystals on insulator is revealed.•Wet anisotropic etching of very thin crystalline layers bounded to oxide.•A contribution for the understanding the onset of the pyramidal hillocks formation.•Possible implementation for the realization of nanocrystal nonvolatile memories. Implementing the Silicon-On-Insulator platform, we reveal an approach to fabricate Si nanocrystals on insulator by a single step, wet anisotropic etching of thin crystalline layers. The evolution of the Si layer was investigated from the onset of the dissolution process up to the development of isolated nanocrystals. Our results also provide several insights into the understanding of the early stages of the hillocks formation characteristic for the anisotropic etching of Si(001). We discuss several related mechanisms and we give experimental evidences that support the stabilization of the pyramidal hillocks apices by short-lived silicate particles.