High-performance bipolar technology for improved ECL power delay

A new shallow trench process for isolation of bipolar devices is shown to allow butting of the emitter-base junction to the field oxide edge, thereby greatly reducing the overall device size and parasitic capacitances. Emitter-coupled logic (ECL) ring-oscillator measurements demonstrate a significant performance leverage, where a delay of 75 ps is obtained at a power of 1.5 mW per gate (power-delay product of 112 fJ ), an improvement of 17% from the nonbutted case. More conventional nonbutted devices have been fabricated with dopant profiles tailored to reduce intrinsic and extrinsic capacitances. These high-performance designs achieve ECL gate delays as small as 26 ps at 5.3 mW, comparable to the fastest ECL delays reported to date.