Method of making a read only memory device

Details Method of making a read only memory device Method of making a read only memory device

1989-01-26

1990-02-27

Hearn, Brian E.

Fishing, trapping, and vermin destroying

437 27, 437 28, 437 41, 437 45, 437 48, 437 51, 437193, 437 49, H01L 21265

Patent

active

049046152

ABSTRACT:
Disclosed are memory cells of a vertical-type read only memory (ROM) having a plurality of MISFETs connected in series. The MISFETs include gate electrodes formed with multiple conductive layers, in which some of the MISFETs are set to the depletion type and at least some of the remaining MISFETs are set to the enhancement type, so as to write information in the memory cells. The information write operation is conducted through at least two steps. Namely, in the first information write step, gate electrodes are used as a mask to implant an impurity; and in the second step, an impurity is implanted through the gate electrodes into the surface of the semiconductor substrate. These steps enable a semiconductor memory device, such as a vertical-type mask ROM having memory cells with a reduced series resistance and being suitable for a high degree of integration, to be produced.
Furthermore, there is disclosed a memory structure of a semiconductor memory device suitable for a higher degree of integration through an arrangement of gate electrodes of multiple layers.

REFERENCES:
patent: Re29660 (1978-06-01), Armstrong
patent: 3653978 (1979-04-01), Robinson et al.
patent: 3876472 (1975-04-01), Polinsky
patent: 4035906 (1977-07-01), Tasch et al.
patent: 4193183 (1980-03-01), Klein
patent: 4295209 (1981-10-01), Dowley
patent: 4328563 (1982-05-01), Schroeder
patent: 4342100 (1982-07-01), Kuo
patent: 4356042 (1982-10-01), Gedaly et al.
patent: 4358889 (1982-11-01), Dickman et al.
patent: 4364167 (1982-12-01), Dowley et al.
patent: 4500975 (1985-02-01), Shirato

Affiliated with

Also associated with

Rating

Method of making a read only memory device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of making a read only memory device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of making a read only memory device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-173989