Fixed resistance high density parallel ROM device

摘要

The present invention provides a fixed resistance sense-routed high density parallel ROM device for maintaining the resistance of a buried N+ region on a sense route constant. When data is read from a ROM cell matrix, the selection of different ROM cell transistors does not change the resistance of the buried N+ region on the sense route and thus enables a simplified design of a sense amplifier. The inactive select gate or transfer gate that is activated by the select line can be isolated by ion implantation for forming a buried P+ isolation and thus avoiding the narrowing or the cutting-off of the width of the active transfer gate or select gate due to ion diffusion.