A 45 K-gate HEMT array with 35-ps DCFL and 50-ps BDCFL gates

A 45 K-gate emitter-coupled-logic (ECL)-compatible array with unbuffered and buffered direct-coupled FET-logic (DCFL and BDCFL) gates has been developed using 0.6- mu m-gate high-electron-mobility transistors (HEMTs) and four-level gold-based interconnects. The high-speed DCFL gates and more functional BDCFL gates are used to replace ECL macros efficiently. The basic cell, equivalent to four three-input NOR gates, consists of 12 enhancement-mode (E-mode) HEMTs, four depletion mode (D-mode) HEMTs, and two source-follower buffers. The basic gate delay times are 35 ps for 0.24-mW unbuffered DCFL gates and 50 ps for 0.38-mW BDCFL gates. The gate array chip is 9.8*9.8 mm and contains 45600 gates. The chip dissipates 11 W in 80% gate use. Silylated polymethyl silsequioxane (PMSS), which has a low dielectric constant of 3, is used for the interlayer dielectrics to reduce wiring delay.<
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