A double-word-line structure in bipolar ECL random access memory

A double-word-line structure to improve the soft error rate in a bipolar ECL RAM that has resistor-loaded and Schottky-barrier-diode (SBD) clamped memory cells is proposed. The resistor in the memory cell is connected to the first word line and the SBD to the second one, whereas both are connected to one word line in the conventional structure. The potential drop between the two word lines causes shifts of SBD clamp potential in unselected cells, and results in large potential difference in the data storage-node pairs and high soft-error immunity. The soft-error rate of the 4-kb RAM with the double-word-line structure is decreased to 1/100 of that of the conventional one, retaining an access time of 5.5 ns and minimum write-pulse width of 2.4 ns. The improvement does not accompany any degradation in electrical characteristics such as access time and write-pulse width.