Silicon nanowire-type devices have demonstrated great potential for label-free bio-detection with selectivity and high sensitivity. However, these devices, generally functionalized through a silane self-assembly chemistry on an oxide layer, suffer from current drift with time due to ion diffusion into the oxide layer. In this paper, we present a surface functionalization process through a H-terminated Si surface on SOI substrated for detection of DNA hybridization. XPS and fluorescence are used to confirm the presence of molecules and check the surface coverage. A H-passivated surface is used in beginning stages in order to protect surface Si from oxidation. This is done by removing native oxide then using NH4 to bind hydrogen to dangling Si Bonds. The functionalized silicon nanowires are obtained by creating an amine terminated sequence using a thin layer of t-BOC (10-N-BOC-Amino-dec-1-ene) protected amine. Once the t-BOC is applied the devices are sealed in a nitrogen rich environment and exposed to 254 nm UV light, during which the double carbon bonds break and re-bond with the dangling surface silicon bonds. This is followed by a deprotection step to leave exposed amine groups on the surface. DNA Oligonucleotides modified by a thiol group can then be covalently linked to the exposed amine groups after a cross-linking step using SSMCC (sulfo-succinimidyl 4-(N=maleimidomethyl) cyclohexane-1-carboxylate). The resulting DNA-modified surface has been demonstrated to produce high selectivity for complementary DNA sequences in solution. XPS data is used to verify surface functionalization at five significant stages throughout the modification process. Specifically they are: (1) the bare Si surface with native oxide, (2) hydrogen-terminated surface, (3) protected amine linked to surface (t-BOC), (4) de-protected amine group linked, and (5) the cross-linking SSMCC applied. Specific attention is paid to oxygen (1s), nitrogen (1s), carbon (1s), and silicon (2p) peaks. The results show reasonable levels of nitrogen (1s) on the surface (3%) compared to reference (control) procedure samples (4.3%) during the protected amine phase. After successful functionalization procedures, the DNA hybridization quality is evaluated by fluorescence intensities. Four trials of interest are used for evaluation: (1) background sample for instrumental calibration and reference, (2) probe DNA only, (3) target DNA only, and finally a sample exposed to probe and then target DNA. Probe DNA referring to DNA Oligonucleotides modified by a thiol group linked to the surface and target DNA referring to DNA desired to hybridize with the probe to verify successful detection. Cy5 (green) is used as the fluorescence marker for probe DNA and Cy3 (red) is used for target DNA. Current efforts are being directed to fabricate Si nanowire biosensors using this functionalization approach for detection of DNA and miRNA hybridization.