GaAs MESFET LSI design using E/D-DCFL circuits

GaAs MESFET LSI design using E/D-DCFL (enhancement/depletion-directly coupled FET logic) circuits is considered. Monte Carlo DC SPICE simulation is used to assess the effect of the FET parameter spread on the functional yield of a chip. It is found that the important factors for obtaining a high functional yield are strict control of the FET characteristics and the stability and uniformity of the supply voltage on the chip. The functional yield model, including the supply voltage drop, agrees well with the results obtained in experiments on a 5 K gate array IC fabricated with 0.8- mu m-gate BP-MESFETs. >