AVS 47th International Symposium
    Processing at the Nanoscale/NANO 6 Wednesday Sessions
       Session NS+NANO6-WeP

Paper NS+NANO6-WeP8
Amino-Terminated Self-Assembled Monolayer on SiO@sub 2@ Surfaces Formed by Chemical Vapor Deposition

Wednesday, October 4, 2000, 11:00 am, Room Exhibit Hall C & D

Session: Poster Session
Presenter: A. Hozumi, National Industrial Research Institute of Nagoya, Japan
Authors: A. Hozumi, National Industrial Research Institute of Nagoya, Japan
H. Sugimura, Graduate School of Nagoya University, Japan
Y. Yokogawa, National Industrial Research Institute of Nagoya, Japan
K. Hayashi, Graduate School of Nagoya University, Japan
T. Kameyama, National Industrial Research Institute of Nagoya, Japan
O. Takai, Graduate School of Nagoya University, Japan
Correspondent: Click to Email
In order to immobilize polymers, neurons, DNA and proteins etc., amino-terminated self-assembled monolayers (SAMs) have been applied. Although chemisorption of aminosilanes at the solid/liquid interface were studied extensively, there have been few reports on preparing aminosilane SAMs from vapor phase. Here, we report on the formation of an amino-terminated SAM on SiO@sub 2@/Si sample substrates on the basis of chemical vapor deposition (CVD). Cleaned SiO@sub 2@/Si substrates were exposed to vapor of aminosilane, that is, N-(6-aminohexyl)-aminopropyltrimethoxysilane (AHAPS) diluted with dehydrate toluene. Following CVD, these samples were washed by a successive immersion in dehydrate ethanol, dehydrate toluene, NaOH (1mM) and HNO@sub 3@ (1mM). This washing process was repeated several cycles. Finally, they were rinsed with MilliQ water and then blown dry with a N@sub 2@ gas stream. We have investigated in detail chemical and electokinetic properties of this amino-terminated SAM. The SiO@sub 2@/Si surface after CVD became hydrophobic showing a water-contact angle of ca. Thickness of the AHAPS-SAM was ca. 1.3 - (±)0.1 nm as estimated by ellipsometry. This value is comparable to the theoretical molecular length of AHAPS, i.e., 1.4 nm. As confirmed by AFM, the surface was very smooth and homogeneous with its roughness being almost identical to that of the SiO@sub 2@/Si substrate. Zeta-potentials of the AHAPS-SAM covered SiO@sub 2@/Si substrate were measured as a function of pH by means of an electrophoretic light scattering spectrophotometer. The surface was charged positively below its isoelectric point of pH 7-8, since the amine groups are easily protonated. Furthermore, we demonstrated micropatterning of the AHAPS-SAM based on the photolithography using an excimer lamp radiating vacuum ultra violet light of 172 nm in wavelength.