A GaAs MESFET 16*16 crosspoint switch at 1700 Mbits/sec

A GaAs MESFET 16x16 crosspoint switch has been fabricated on a 3-mm x 4-mm chip using a 1-μm super buffer logic (SBL) design containing approximately 10000 FETs and operating at 800 mW of power. A 99% confidence bit error rate (BER) better than 1*10/sup -3/ was obtained at 1.7 Gb/s rate using a 2/sup 7/ -1 pseudorandom NRZ (nonreturn-to-zero) sequence. The BER test was done on one path using a probe card. The chip has 255 out of 256 good crosspoints. The bad crosspoint was a repeating error from a mask defect. An advanced refractory-gate MESFET process was used to fabricate the chip. A lightly doped drain structure was used to reduce parasitic gate capacitance while maintaining acceptable source resistance, to reduce short-channel effects, to increase breakdown voltage compared to devices where the heavy source/drain implant is directly self-aligned to the gate edge.<
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