A memory system comprising uncased integrated circuits, evaporated wires, and magnetic, thin-film storage elements has been fabricated and tested. The 1536-bit memory system is contained on one side of a 3-by 4 1/2-inch glass substrate. All system wiring on the substrate is formed by evaporating aluminum through masks. All system circuits are contained on 182 silicon chips, each 0.050-inch square, and the chips are ultrasonically bonded directly to the evaporated aluminum. Data are presented on the operation of the selection system, of the recirculation loops, and of a portion of the memory system. Operation of the complete memory system was precluded by oscillations which developed in the system as recirculation loops were added. All subsections of the memory system function properly except for the recirculatinn loops. The origin of the oscillations and the techniques for eliminating them are discussed. The data obtained in fabricating and testing partially populated systems indicate that the fabrication techniques are practical.

THE DESIGN of an evaporated memory system presently under development and the fabrication of selected parts of the system will be described in this paper. A completely evaporated system is not possible now since suitable evaporated active elements are not available. but the availability of suitable elements is anticipated Chip transistors and diodes and electroplated magnetic films are used in the memory; all other parts memory are evaporated.

Planar, thin film magnetic memory arrays of 4×4 and 64×24 elements have been fabricated from evaporated matrix wiring and insulating layers. Four metallic and three insulating layers were evaporated sequentially in a vacuum chamber without breaking the vacuum. The magnetic element is an electroplated ternary alloy of nickel-iron-phosphorus 0.13 mm (0.005-in.) in diameter and a few hundred Å thick. The film has an anisotropy field of about 1 Oe and switches in 10 nsec with an applied word drive current of 35 mA. Sense and cancellation lines and dummy bit lines are used to cancel interwire coupling. Disturb tests were performed with up to 104 disturb pulses being applied along the easy axis. The outputs from films with Hc/Hk≈2 were decreased by less than 10% when disturbed in this manner. An evaporated memory array made with highly inverted films may be usable as a high-speed, low-current memory storage device.