Microstructural Study of a Passivation Layer on GaAs: An Application of X-Ray Reflectivity Under Grazing Angles Using a Synchrotron Source

Abstract

X-ray specular reflectivities of GaAs samples passivated with a thin film of (3-mercaptopropyl)-trimethoxysilane (MPT) have been studied using bending-magnet synchrotron radiation. Various preparation procedures covering etching the GaAs, MPT deposition and its baking have been investigated. An oxide film is always observed between the GaAs and MPT films. The microstructural parameters, such as film thickness, density and interfacial roughness (including the external surface), have been determined from appropriate modeling of the reflectivity. The surface roughness has been compared with a direct measurement using tapping-mode atomic force microscopy. The results are discussed with reference to the potential applications of GaAs as a biosensor.

In vitro assessment of the biocompatibility of chemically modified GaAs surfaces

“…These substances have been shown to cause cell death (6). In recent years a number of researchers have investigated the possibility of chemically modifying the surface of GaAs in order to slow or prevent the release of toxic materials when the surface comes into contact with living cells (7,8). A way one can increase the biocompatibility of the surface is through the use of a self-assembled monolayer (SAM) (9,10).…”