Method of making multi-stage ROM structure

Details Method of making multi-stage ROM structure Method of making multi-stage ROM structure

1997-04-15

1999-03-16

Chaudhari, Chandra

Semiconductor device manufacturing: process

Making field effect device having pair of active regions...

Having insulated gate

438270, H01L 218246

Patent

active

058829717

ABSTRACT:
A multi-stage read only memory (ROM) device and a method for fabricating the same. The device includes a source/drain pole and a gate in a trench, wherein the gate intersects the source/drain pole in an angle to form a number of memory cells. The fabrication of the multi-stage ROM includes two encoding process. The first encoding process includes implantation of impurity ions in a portion of memory cells to adjust the threshold voltage, so that some of the memory cells have a first threshold voltage and the others have a second threshold voltage. The second encoding process includes forming a spacer on the opposite side-walls of the gate trench of a portion of the memory cells, so that some of the memory cells have a first effective channel width and the others have a second effective channel width. As a result, the memory cells of a ROM are of four types with different combinations of threshold voltages and effective channel widths.

REFERENCES:
patent: 5429973 (1995-07-01), Hong
patent: 5504025 (1996-04-01), Fong-Chun et al.
patent: 5595927 (1997-01-01), Chen et al.
patent: 5627091 (1997-05-01), Hong

Affiliated with

Also associated with

Rating

Method of making multi-stage ROM structure 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 multi-stage ROM structure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of making multi-stage ROM structure will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-817141