Aminosilane film oil mica is investigated in this work for further use as a substrate for DNA immobilization. We study the deposition of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AAPS) on mica surfaces by atomic force microscopy, X-ray photoelectron spectroscopy, and contact angle measurements. Deposition both in aqueous solution and in vapor-phase is explored. In aqueous solution, it is found that the interactions of molecules with the mica surface are pH-dependent. In the case of vapor phase deposition, a multilayer film composed of a first monolayer and successive bilayers is obtained. This is the first observation of the organization of aminosilane films oil mica.