Fabrication of Small AlGaAs/GaAs HBT's for Integrated Circuits Using New Bridged Base Electrode Technology

概要

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This paper describes small AlGaAs/GaAs HBT's for low-power and high-speed integrated circuits. The device fabrication is based on a new bridged base electrode technology that permits emitter width to be defined down to μm. The new technology features oxygen-ion implantation for emitter-base junction isolation and zinc diffusion for extrinsic base formation. The oxygen-ion implanted emitter-base junction edge has been shown to provide a periphery recombination current much lower than that for the previous proton implanted edge, the result being a much higher current gain particularly in small devices. The zinc diffusion offers high device yield and good uniformity in device characteristics even for a very thin (0.04 μm) base structure. An HBT with emitter dimensions of 1×2.4 μm^2 yields an f_T of 103 GHz and an f_<max> of 62 GHz, demonstrating that the new technology has a significant advantage in reducing the parasitic elements of small devices. Fabricated one-by-eight static frequency dividers and one-by-four/one-by-five two-modulus prescalers operate at frequencies over 10 GHz. The emitters of HBT's used in the divider are 1×2.4 μm^2 in size, which is the smallest ever reported for AlGaAs/GaAs HBT IC's. These results indicate that the bridged base electrode technology is promising for developing a variety of high-speed HBT IC's.
社団法人電子情報通信学会の論文
1994-09-25