E-beam fabrication of bipolar VLSI logic, including a ∼ 5K gate 16-bit I2L microprocessor

Direct electron-beam fabrication of 1.25 µm I²L and ISL logic circuits for VLSI is described. The I²L work is highlighted by the SBP9989E, a 55% linearly scaled version of the ∼5K gate, 16-bit SBP9989 microprocessor. The SBP9989E is TTL compatible, has an active area equal to 30% of the full-size chip, and shows a speed improvement of 2X at one-half the power of the full-size SBP9989. ISL ring oscillators exhibited minimum gate delays of 0.55 ns at 50 µA with a fan out of one and 0.62 ns at 70 µA with a fan out of four.