Write once read only memory employing charge trapping in insulators

摘要

Structures and methods for write once read only memory employing charge trapping in insulators are provided. The write once read only memory cell includes a metal oxide semiconductor field effect transistor having a first source/drain region, a second source/drain region, a channel region between the first and the second source/drain regions, and a gate separated from the channel region by a gate insulator. A plug couples the first source/drain region to an array plate. A bitline is coupled to the second source/drain region. The MOSFET can be programmed by operation in a reverse direction trapping charge in the gate insulator adjacent to the first source/drain region such that the programmed MOSFET operates at reduced drain source current when read in a forward direction.