Front‐End‐of‐Line Integration of Graphene Oxide for Graphene‐Based Electrical Platforms

Abstract Scalable and routine integration of chemically exfoliated, graphene‐based materials such as graphene oxide (GO) and reduced graphene oxide (rGO) into standard microelectronic fabrication is a tremendous technological challenge, blocking their advancement toward real applications. A unique approach for wafer‐scale fabrication of rGO devices by a synergistic combination of chemically exfoliated GO with photolithography processing is realized. Using graphite powder as source material, a GO solution is produced in a newly optimized, low‐temperature exfoliation and desalination protocol, resulting in high‐quality GO and confirmed by various characterization techniques. As substrates, 4 in. Si/SiO₂ or glass wafers were first silanized in a well‐controlled, gas‐phase procedure. Large‐area GO thin films are then realized by standard spin‐coating resulting in highly homogeneous, covalently bound layers of controllable thicknesses of 3–7 nm depending on the amount of spin‐coatings. The robust thin films undergo routine photolithography for device fabrication, including reduction via thermal annealing into conductive rGO. The top‐down fabricated rGO devices display high uniformity with electrical resistances varying within only one order of magnitude over wafer‐scale and device yields as high as ≈93% on a wafer. The novel front‐end‐of‐line GO integration protocol offers robust electrical performances for future implementation toward various sensor applications.