Browse Prior Art Database

Programmable Memory Circuits

IP.com Disclosure Number: IPCOM000083191D
Original Publication Date: 1975-Apr-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Ho, IT: AUTHOR [+6]

Abstract

Circuits are described utilizing integrated circuit resistors having values tailored by ion implantation. Each resistor is formed to have a specific value. Then, by ion implantation, the value of the resistor is raised, by as much as 20%. The use of increased current through the resistor sequentially returns it to its original value, thereby enabling programming.

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Programmable Memory Circuits

Circuits are described utilizing integrated circuit resistors having values tailored by ion implantation. Each resistor is formed to have a specific value. Then, by ion implantation, the value of the resistor is raised, by as much as 20%. The use of increased current through the resistor sequentially returns it to its original value, thereby enabling programming.

Fig. 1 shows a programmable read-only memory (ROM) wherein each ROM bit consists of a PN junction in series with an ion implanted resistor RT. The writing or programming process is accomplished by directing a large current through the selected diode 11, 12, 21 or 22 and the related resistor RT, in either steady state or pulse-power mode. The resulting thermal setting of the resistor substantially lowers its resistance value. thereby setting the memory element to a desired characteristic.

Fig. 2 shows a programmable latent image memory also utilizing ion implanted resistors RT1 and RT2. Thus, one of the two resistors in the cell can be thermally set by sending a large current through it. The choice of which resistor is thermally set is equivalent to writing a ROM bit on top of a random- access memory bit, thereby forming a latent image memory.

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