The Use of Graphene as a Solid State Diffusion Barrier

Résumé du livre

Conventional thin film diffusion barriers consist of three dimensional bulk films with high chemical and thermal stabilities. The purpose of the barrier material is to prevent intermixing or penetration from the two materials that encase the barrier material. Adhesion to both top and bottom materials is critical to the success of the barrier. The aim of this thesis is to test the effectiveness of a single atomic layer of graphene as a solid state diffusion barrier for common semiconductor based conductors. Two classes of metals were studied, physisorbed metals, which form a weak bond with graphene and chemisorbed metals, which are strongly bonded to graphene. E-beam deposited metal films on silicon were annealed with and without graphene to determine if graphene will prevent metal silicide layers from forming. Thin layers of metal films on silica were studied with a graphene barrier to determine if the graphene would prevent diffusion into the underlying substrate at various temperatures. In addition, a graphene diffusion barrier was used to study the inter-diffusion of a sandwich structure of nickel and gold on Mg-doped p-GaN wafers. In order to synthesize graphene, a custom vacuum based Rapid Thermal Processing (RTP) system was built. The RTP system was utilized to explore the growth of graphene with various chemistries of methane and hydrogen at different vacuum levels and temperatures. Analytical techniques such as X-ray Photoelectron Spectroscopy, Raman Spectroscopy,