Retention in nvm with top or bottom injection

Abstract

Retention of charges in a nonvolatile memory (NVM) cell having a nitride-based injector (such as SiN, SIRN, SiON) for facilitating injection of holes into a charge-storage layer (for NROM, nitride) of a charge-storage stack (for NROM, ONO) may be improved by providing an insulating layer (for NROM, oxide) between the charge-storage layer and the injector has a thickness of at least 3 nm. Top and bottom injectors are disclosed. Methods of operating NVM cells are disclosed. The NVM cell may be NROM, SONOS, or other oxide-nitride technology NVM cells such as SANOS, MANOS, TANOS.

1 . A method of operating an NVM cell having a substrate, a charge-storage stack and a gate, comprising:
 programming using electron injection from the substrate;   erasing using hole tunneling from a hole source, which hole source is either the gate or the channel; and   wherein hole tunneling is facilitated through an injector including both a hole permissive material and an insulator layer.   
     
     
         2 . The method of  claim 1 , wherein erasing is performed by:
 applying approximately +10 volts to the gate; and   applying approximately −8 volts to the substrate.   
     
     
         3 . The method of  claim 1 , wherein erasing is performed by:
 applying approximately +10 volts to the substrate; and   applying approximately −8 volts to the gate.   
     
     
         4 . The method of  claim 1 , wherein erasing is performed by: applying a potential difference of 14-18 volts between the gate and the substrate. 
     
     
         5 . The method of  claim 1 , wherein: the electron injection is performed using a technique selected from the group consisting of channel hot electron (CHE) injection and channel initiated secondary electron (CHISEL) injection.