Cryotron storage cells for random access memories

Cryotron storage cells are attractive for random access memory because of their broad tolerances. In the past, their lower size limit has been set by the fact that their read-out signal becomes too small and short to be sensed by conventional amplifiers. A new sensing method has been developed which removes this limitation, so that the lower limit of cell size is now determined by fabrication technology only. This paper describes this technique as well as a number of old and new cryotron cells compatible with it. Cell dimensions are calculated in terms of fabrication parameters and a comparison of the densities of various bit and word organized designs is made.