Sub-100 pS silicon bipolar ECL circuit operation at liquid nitrogen temperatures

A two-dimensional device simulator is used to examine the various low-temperature profile design strategies for silicon bipolar transistors. It is found that a relaxed scaling approach offers the best overall results for high speed circuit operation at liquid nitrogen (LN2) temperatures. To support these calculations, experimental results which demonstrate that sub-100-pS emitter-coupled-logic circuit (ECL) operation at LN2 temperature is achievable are reported. Design tradeoffs are discussed on the basis of the experimental results.