SEMICONDUCTOR MEMORY AND PROGRAMMING METHOD THEREFOR

摘要

A read-only memory cell formed from a single insulated gate field-effect transistor may be selectively programmed by being operated under suitable biasing conditions to cause some of the electrons flowing between the source and drain to acquire sufficient energy to be injected into and trapped in the insulating material separating the channel from the gate electrode. The trapped electrons cause a change in the current-voltage characteristics of the transistor which may be detected during reading of the memory cell most easily by reversing the polarity of the source and the drain. An array of such cells may be utilized as a ROM, PROM or EPROM.