A research team from the University of Texas and German nanotechnology company Aixtron have worked out a way to make wafer-scale graphene measuring between 100 and 300mm.
The research offers the prospect of integrating carbon-based graphene, which is just one atom thick, with silicon on a semi-industrial scale. Until now, graphene has proved difficult to manufacture in sufficient area, quantity and reliability for viable use in processors.
IBM research scientist Shu-Jen Han led a project that announced the creation of a wafer-scale graphene circuit in January of this year but did not solve the issue of reliable industrial-scale production. The polycrystalline graphene developed by IBM has improved carrier transport characteristics and fewer defects, enabling the team to manufacture 25,000 graphene field-effect transistors from lab-generated graphene film.
The largest applications of high-performance graphene will likely be realized when combined with ubiquitous Si very large scale integrated (VLSI) technology, affording a new portfolio of “back end of the line” devices including graphene radio frequency transistors, heat and transparent conductors, interconnects, mechanical actuators, sensors, and optical devices. To this end, we investigate the scalable growth of polycrystalline graphene through chemical vapor deposition (CVD) and its integration with Si VLSI technology. The large-area Raman mapping on CVD polycrystalline graphene on 150 and 300 mm wafers reveals over 95% monolayer uniformity with negligible
defects. About 26 000 graphene field-effect transistors were realized, and statistical evaluation indicates a device yield of ∼74% is achieved, 20% higher than previous reports. About 18% of devices show mobility of over 3000 cm squared per(V s), more than 3 times higher than prior results obtained over the same range from CVD polycrystalline graphene. The peak mobility observed here is ∼40% higher than the peak mobility values reported for single-crystalline graphene, a major advancement for polycrystalline graphene that can be readily manufactured. Intrinsic graphene features such as soft current saturation and three-region output characteristics at high field have also been observed on wafer-scale CVD graphene on which frequency doubler and amplifiers are demonstrated as well. Our growth and transport results on scalable CVD graphene have enabled 300 mm synthesis instrumentation that is now commercially available.