ANNEALING TEMPERATURE EFFECT ON THE SENSITIVITY OF SIGE NANOWIRE FOR BIO-SENSOR

Abstract

Nanowire is widely used in biological sensor because it has the high surface-to-volume ratio. Germanium (Ge) would be beneficial to enhance the sensitivity of silicon nanowire for bio-sensor. In this study, we have successfully fabricated the SiGe on Insulator (SGOI) nanowires with different annealing temperature by side-wall spacer technique, respectively. The 3-amino-propyltrime-thoxy-silane (APTS) is used to modify the surface, which can connect the bio-linker. Nanowire is considered as a resistance, and the change of conductance (Delta G) and sensitivity (S) of different samples corresponding to APTS treatment were investigated. As annealing temperature was elevated from 800 to 950 degrees C, the SiGe nanowire exhibited increasing sensitivity in the chemical detection. However, it was noted that degradation of sensitivity was observed as the annealing temperature increases up to 1000 degrees C. This behavior may be associated with the reduction of the Ge concentration at the surface of SiGe nanowire due to high-temperature diffusion of Ge in Si. So, temperature is a key parameter in the annealing process producing two effects: repairs of defects and Ge diffusion. There would be an optimal annealing temperature between 900 and 1000 degrees C.