3-Aminopropyltriethoxylsilane (APS), N-[3-(Trimethoxylsilyl)propyl]-ethylenediamine, N-[3-(Trimethoxylsilyl)propyl]diethyenetriamine were assembled onto silicon surfaces. Using a mixture of acetone and water as solvent, factors which would affect the formation of amino-terminated self-assembled monolayers (SAMs), such as water content in solvent and reaction time, were investigated. The structural information of SAMs was collected from contact angle measurements, ellipsometric thickness measurements and X-ray photoelectronic spectroscopy. Reaction time and water content in solvent produced dominant effects on the formation of amino terminated SAMs. The method introduced in this paper also presents a simple and controllable way to prepare amino-terminated SAMS. Copyright © 2012 John Wiley & Sons, Ltd.