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Carbon Electronics for RF Applications (CERA)
Program Manager: Dr. Michael Fritze
The Carbon Electronics for RF Applications (CERA) program will develop wafer-scale graphene synthesis approaches and ultra-high-speed, low-power graphene-channel field effect transistors for RF/mm-wave circuits. The many desirable material properties of the novel graphene films, including ultra-high mobility, high saturation velocity, high current carrying capability, excellent thermal conductivity, ultra-thin geometry and the potential to integrate with traditional CMOS processes, offer the potential for graphene-based transistors with high promise for high-performance, high-integration-density RF system-on-chip applications. For this reason, the CERA program focuses on developing innovative approaches that enable revolutionary advances in materials science, epitaxial growth, transistor development, and RF circuit design. Desirable properties of CERA transistors include high mobility, high cutoff frequencies (ft and fmax), high transconductance, low noise, and low voltage operation. In addition, graphene-channel devices also offer low parasitic resistances, excellent electrostatic scaling and high integration potential with silicon CMOS. The CERA program will culminate in a demonstration of high performance W-band (≥ 90 GHz) low noise amplifiers (NF ≤ 1dB) making use of graphene transistors on wafers with diameters ≥ 8 inches.
The CERA program will develop techniques to synthesize high quality graphene films on a wafer scale, to engineer a graphene bandgap, to build high performance RF transistors, and to integrate the transistors for a low-power high-performance low noise amplifier. The possible synthesis methods include SiC-based thermalization, chemical vapor deposition, and molecular beam epitaxy techniques. The graphene FETs will be fabricated by utilizing either semi-metal or semiconducting channels. Numerous technical challenges will be overcome that include monolayer control of the graphene synthesis process over large areas, demonstration of high mobility graphene-channel FETs, fabrication of low-resistance contacts, nanometer-scale patterning of graphene ribbons, and development of accurate device models for RF circuit design. Phase I of CERA will concentrate on developing synthesis processes for graphene thin films and demonstrating the feasibility of fabricating graphene-based field effect transistors (FET). Phase II will significantly increase the area of the graphene films and control the thickness of the graphene down to monolayer accuracy. In addition, ultra-high speed graphene transistors will also be demonstrated. Phase III will further optimize the transistor performance and increase the active area of graphene to cover an 8-inch wafer with a demonstration of W-band low noise amplifier circuit to validate the material and transistor goals. The success of the development of graphene-based RF electronics will lead to ultra-high-speed, ultra-low-noise, ultra-low power RF circuits, which will have significant impact on communications, electronic warfare, radar, and many other key DoD systems.