CRYOELECTRIC RANDOM ACCESS MEMORY PHASE Ⅲ

摘要

This report is Volume I of a two-volume final report covering the Third and Final Phase of a program for the development of a large-capacity, random-access cry electric memory. Volume I deals principally with theoretical studies that were undertaken on the cry electric memory. These studies have shown that the detailed electrodynamic behavior of continuous film superconducting memories can be specified. The important parameters to be controlled in fabrication to obtain the uniformity necessary for practical realization are set forth. It is shown that the most important single parameter is the uniformity of the grain structure in the tin memory film itself. Size variations greater than 2:1 of the micro crystallites of tin forming the memory film will make it practically impossible to build a plane with a uniformity of drive currents that is satisfactory for proper operation in a memory stack. Another important parameter is the geometrical control of the width of the drive and sense lines when other than cavity sensing techniques are used. It is also shown that cavity sensing works quite satisfactorily for small structures, but is not usable for large structures. Two different expressions have been developed from two different points of view that give essentially the same answer with regard to the variation in sense signal for cavity sensing structures over a plane. A practically exact solution to the output from a line sense structure is developed, and it is shown that a 1-mV sense signal can reasonably be expected for cry electric memory cells of a size such that 10,000 can be put in one square inch. The vortex theory of superconductive memories is fully developed and provides another method of attack in specifying the electrodynamic behavior of continuous film memory planes.